physics - narayana schools science sankranthi holiday package narayana group of schools page 13 of...

AP_CLASS-X_PHYSICAL SCIENCE SANKRANTHI HOLIDAY PACKAGE

NARAYANA GROUP OF SCHOOLS 3 of 87

PHYSICS ELECTRICITY

1 MARK 1. What is represented by joule/coulomb? 2. A charge of 2C moves between two plates, maintained at a potential difference

of 1V. What is the energy acquired by the charge? 3. Why are copper wires used as connecting wires? 4. A wire of resistivity 10 ohm meter is stretched to double its length. What is its

new resistivity? 5. What should be the resistance of an ammeter? 6. What should be the resistance of a Voltmeter? 7. Which has more resistance: 100W bulb or 60W bulb? 8. What happens to the current in a circuit if its resistance is doubled? 9. What happens to the resistance of a circuit if the current through it is

doubled? 10. How does the resistance of a wire depend upon its radius? 11. Two wires are of the same length, same radius, but one of them is of

copperand the other is of iron. Which will have more resistance? 12. Two wires of same material and same length have radii r1 and r2.

Comparetheir resistances. 13. How much work is done in moving a charge of 3coulomb from a point at

thevolts 115V to a point at 125V? 14. Ammeter burns out when connected in parallel. Give reasons. 15. Define drift velocity of free electron? 16. Define power. Give its SI unit. 17. A wire of resistance R is bent in form of a closed circle, what is the resistance

across a diameter of the circle? 18. A charge of 6 C is moved between two points P and Q having, potential

10Vand 5V respectively. Find the amount of work done. 19. Name the physical quantity whose SI unit is JC-1. 20. Two wires of equal cross sectional area, one of copper and other of

manganinhave same resistance. Which one will be longer? 21. Define resistivity. Write the S.I. unit of resistivity. 22. Define electric current. Give its SI unit. 23. On what factors does the resistance of a conductor depend? 24. What determines the rate at which energy is delivered by a current? 25. An electric motor takes 5 A from a 220 V line. Determine the power of

themotor and the energy consumed in 2 h. 26. What is the S.I. unit of charge?


NARAYANA GROUP OF SCHOOLS Page 14 of 87

27. State ohm’s law. 28. Define electric resistance. 29. Compute the heat generated while transferring 96000 coulomb of charge

inone hour through a potential difference of 50 V. 30. When a 12 V battery is connected across an unknown resistor, there is

acurrent of 2.5mA in the circuit. Find the value of the resistance of the resistor.

31. What is the unit of resistance? 32. The potential difference between the terminals of an electrical iron is 240

Vand the current is 5.0 A. What is resistance of the electric iron? 33. Why do we use copper wires as connecting wires? 34. How many joules are in one watt-hour? 35. What is the nature of the graph between potential difference and the

electriccurrent flowing through an ohmic conductor. 36. A student carries out an experiment and plots the V-I graph of three

samplesof Nichrome wire with resistances R1, R2 and R3 respectively as shown in thefigure. Which of the following is live?

(A) R1 <R2<R3 (B) R2 > R3> R1 (C) R1>R2> R3 (D) R1 =R2 =R3

37. Which of the following expressions does not represent the electric power in

thecircuit? (A) VI (B) I2/R (C) V2/R (D) I2 R 38. If the current I through a resistor is increased by 100% then what is the

increased in power dissipation? (Assume temperature remain unchanged). 39. A student says that the resistance of two wires of same length and same area

of cross section is same. This statement is correct if (a) Both wires are of different materials. (b) Both wires are made of same material and are at different temperature. (c) Both wires are made of same material and are at same temperature. (d) Both wires are made of different materials and are at the same

temperature. 40. Calculate the number of electron consisting one coulomb of charge? 41. Alloys are used in electrical heating devices rather than pure metals.

Givereason.



42. Define one ohm. 43. Two resistances each of 2 ohm are connected in parallel. Find their

equivalentresistance. 44. In an experiment ohm’s law, a student obtained a graph as shown in the

diagram. What is the value of resistance?

45. Three resistors are connected in series. What is the equivalent resistance ofthe

combination? 46. What is the maximum resistance which can be made using five resistor eachof

1/5Ω. 47. What is the minimum resistance which can be made using five resistor eachof

1/5Ω. 48. Two wires of same material are having length L and 2L. Compare

theirresistance and resistivity. 49. What is the difference between a conductor and an insulator? 50. What are the disadvantages and advantages of heating effect of current? 2 Marks: 1. What happens to the resistance of a circuit if the current through it is

doubted? 2. Two wires are of same length, same radius but one of them is of copper &

the other is of iron. Which will have more resistance? 3. Given a resistors each of resistors R. how will you combine them to get the

i. Maximum & ii Minimum effective resistance? 4. A wire of length ‘l’ &resistance ‘R’ is stretched so that its length is doubled.

How will it (a) Resistance change (b) Resistivity change? 5. Two students perform the experiments series & parallel combinations of

two given resistors R1& R2 plot the following V-I graph Which of the graph is (are) correctly labelled in terms of words “series” & “Parallel “. Justify your answer.



6. A house hole uses the following electric appliances:

(i) Refrigerator of rating 400W for 10 hours each day (ii) Two electric fans of rating 80 W each for 12 hours each day.

Calculate the electricity bill of the household for the month of June if the cost per unit of electric energy is Rs. 3.00.

7. A wire of resistance 4 Ω is bent in the shape of circle. What is the resistance between two diametrically opposite ends?

8. A current of 4 A flows in a wire of resistance 60 Ω. Calculate electricalenergy consumed in 2 minutes.

9. V-I graph for two resistors is given. Which of the two has minimumresistance?

10. A current of 0.5 A is drawn by a filament of an electric bulb for 10

minutes. Find the amount of electric charge that flows through the circuit. 11. Which device is used to measure the electric current? 12. Why the filament of bulb has high melting point? 13. What is the relationship between power (p), current (I) & voltage (v) 14. What would be new resistance if length of the conductor is doubled &cross

–section area is halved? 15. Find the effective resistance between A &B.



16. Three resistances of 2Ω, 3Ω & 5Ω are connected in electric circuit. Find a. Maximum effective resistance. b. Minimum effective resistance.

17. State ohm’s law? 18. Draw voltage current graph for ohmic conductor. 19. Find the equivalent resistance between point A & B.

20. Find potential difference across 4 Ω. 21. When a 12v battery is connected across an unknown resistor, there is a

current of 2.5mA in the circuit. Find the value of resistance of resistor. 22. A copper wire has diameter 0.5mm & resistivity of 1.6×10-8 Ω m.What will be

the length of this wire to make its resistance 10 Ω.? 23. An electric bulb is rated 220V& 100W. What is the power consumed by the

bulb when it is connected to 110V? 24. A piece of wire of resistance R is cut into 10 equal parts .what will be the

resistance of each part? 25. Convert 1 kWh into joule? 26. An electric bulb is connected to a 220V generator.The currentis 0.50 A. What

is the power of the bulb? 27. 100 J of heat is produced each second in a 4 Ω resistance. Find the potential

difference across the resistor. 28. A wire of resistivity ‘ρ’ is stretched to double its length. What is the new

resistivity? 29. How will you join three resistances,each of 2 Ω so that the effective resistance

is 3Ω? 30. What happens to the current in a circuit if its resistance is doubled?



3 MARKS: 1. What is Joule’s heating effect? How can it be demonstrated experimentally?

List its four applications in daily life. 2. How will you conclude that the same potential difference (voltage) exists

across three resistors connected in a parallel arrangement to a battery? 3. How will you infer with the help of an experiment that the same current flows

through every part of the circuit containing three resistances in series connected to a battery?

4. What is electrical resistivity of a material? What is its unit? Describe an experiment to study the factors on which the resistance of conducting wire depends.

5. State Ohm’s law? How can it be verified experimentally? Does it hold good under all conditions? Comment.

6. Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit another set of three bulbs of the same wattage are connected in parallel to the same source. Will the bulb in the two circuits glow with the same brightness? Justify your answer.

7. A current of 1 ampere flows in a series circuit containing an electric lamp and a conductor of 5 Ω when connected to a 10 V battery. Calculate the resistance of the electric lamp.

8. Why is parallel arrangement used in domestic wiring? 9. How does use of a fuse wire protect electrical appliances? 10. Should the resistance of an ammeter be low or high? Give reason. 11. Write difference between electric power and electric energy. 12. An electric iron of 1kW is operated at 220V. Find which of the following fuses

that respectively rated at 1A, 3A and 5A can be used in it. 13. Calculate the resistance of 1km long copper wire of radius 1mm. Resistivity of

copper is 1.72x10-8 Ωm. 14. What is the usual colour code followed for connecting live, neutral and

earthwires? Why is it so important? 15. What is the difference between an electromagnet and a permanent magnet? 16. An electric iron is used on a 240V supply and draws a current of 4 Ampere?

(a) What is its power? (b) What is its resistance? (c) What is the cost of using the iron for the month of January 10 hours a day if 1 kWh costs Rs.3.40?

17. Electricians wear rubber sandals or shoes or rubber hand gloves while working, why?

18. A current of 2A flows through a 12V car headlight bulb for 6 minutes. How much energy transfer occurs during this time?

19. How is the potential difference maintained across the ends of a conductor? What are non-ohmic conductors?



20. How much work is done in moving a body carrying charge equivalent to that on 5 x 1019 electrons from a point at 25 volts to a point at 40 volts?

5 MARKS: 1. Give the principle, construction and working of an electric motor. 2. Describe the construction and working of an electromagnet. Mention the

factors on which its strength depends. 3. A resistor of 8 ohm is connected in parallel with another resistor X. The

resultant resistance of the combination is 4.8 ohm . What is the value of X? 4. Two wires A and B are of equal lengths, different cross-sectional areas and

made of the same metal. (i) Name the property which is same for both the wires. (ii) Name the property which is different for both the wires.

(iii) If the resistance of wire A is four times the resistance of wire B, calculate (a)the ratio of the cross-sectional areas of the wires. (b)the ratio of the radii of the wires. 5. (a) Differentiate resistance and resistivity

(b) The ratio of resistivities of two materials a and b is 1:2, ratio of their length is 3:4 and if the ratio of radii is 2:3 find the ratio of resistance of a and b.

MAGNETIC EFFECTS OF ELECTRIC CURRENT 1 MARK 1. Why does the bulk of iron fillings stick to the ends of a bar magnet and not at

its centre? 2. If the frequency of A.C. is 50 Hz. Then how many times it is changing its

direction in 1 second? 3. What is the pattern of the magnetic field lines around a straight conductor

carrying current? 4. If the current is flowing in the direction of advancement of screw, then what is

the direction of magnetic field lines? 5. How can you say that the magnetic field is uniform inside the solenoid? 6. Which property of a proton will change while it moves freely in a magnetic

field? 7. According to Flemings right hand rule, which part of right hand indicate the

movement of conductor? 8. If the number of turns of a circular current carrying coil are doubled, then

how will the magnetic field produced by it changes? 9. In which position the force on conductor is maximum, when it is placed in

uniform magnetic field?



10. A current through a horizontal power line flows in north to south direction. What is the direction of magnetic field (i) at a point directly below it and (ii) at a point directly above it?

11. Electric appliances like electric –press, toaster, fans etc are connected to electric mains through three-pin plug. Why?

12. Name any two devices which uses permanent magnets. 13. Give two uses of electromagnet. 14. Why can’t two magnetic field lines ever intersect? 15. Can a 5A fuse be used in wire carrying 15A current? Why? 16. Give the factors that affect the strength of magnetic field at a point due to

straight current carrying conductor. 17. Why is the earth pin thicker and longer than the live and the neutral pins? 18. What is the magnetic field intensity inside a long straight solenoid carrying

current? 19. A positively charged particle projected towards West is deflected towards North

by magnetic field. What is the direction of magnetic field. 20. What is the role of slip ring in an electric motor? 21. What will be the frequency of an A.C. if its direction changes after every .01s? 22. An A.C. has a frequency of 50Hz. How many times does it change its direction

in one second? 23. Draw the pattern of magnetic field lines of a current carrying solenoid. 24. Write one application of magnetic field of current carrying solenoid. 25. Sketch magnetic field lines around a current carrying straight conductor. 26. Why does a current carrying conductor kept in a magnetic field experience

force? 27. Name and state the rule used to determine the direction of magnetic force. 28. Give one important advantage of A.C. over D.C. 29. Give the circuit symbol for a fuse. 30. What is the working principle of A.C. Generator? 31. How can you convert an A.C. into D.C. Generator? 32. What is magnetic field? 33. Draw magnetic field lines for a bar magnet. 34. What is electromagnetic induction? 35. Name the elements of earth’s magnetic field. 36. If the current in a wire is flowing in the vertically downward direction and a

magnetic field is applied from west to east, then what is the direction of force on the wire?

37. What do you understand by the term ‘magnetic field’? 38. At the time of short circuit the value of electric current in the circuit: (a) Increases heavily (b) zero (c) reduces slowly (d) none of these



39. List two properties of magnetic field lines. 40. What is the role of the two conducting stationary brushes in a simple electric

motor? 41. What does the divergence of magnetic field lines near the ends of a current

carrying straight solenoid indicate? 42. What does the direction of thumb indicate in the right-hand thumb rule. In

what way this rule is different from Fleming’s left-hand rule? 43. A magnetic compass shows a deflection when placed near a current carrying

wire. How will the deflection of the compass get affected if the current in the wire is increased?

44. Under what conditions permanent electromagnet is obtained if a current carrying solenoid is used?

45. The most important safety method used for protecting home appliances from short circuiting or overloading is

(a) earthing (b) use of fuse (c) use of stabilizers (d) use of electric meter 46. To convert an AC generator into DC generator (a) split-ring type commutator must be used (b) slip rings and brushes must be used (c) a stronger magnetic field has to be used (d) a rectangular wire loop has to be used 47. The strength of magnetic field inside a long current carrying straight solenoid

is (a) more at the ends than at the centre (b) minimum in the middle (c) same at all points (d) found to increase from one end to the other 48. Choose the incorrect statement (a) Fleming’s right-hand rule is a simple rule to know the direction of induced

current (b) The right-hand thumb rule is used to find the direction of magnetic fields

due to current carrying conductors (c) The difference between the direct and alternating currents is that the direct

current always flows in one direction, whereas the alternating current reverses its direction periodically

(d) In India, the AC changes direction after every 1 50 second 49. Commercial electric motors do not use (a) an electromagnet to rotate the armature (b) effectively large number of turns of conducting wire in the current

carryingcoil (c) a permanent magnet to rotate the armature



(d) a soft iron core on which the coil is wound 50. Give SI unit of magnetic field intensity.

2 Marks: 1. A rectangular coil, ABCD is lying in the plane of the page as shown. A bar

magnet with its north pole pointing towards the page is moved along a direction perpendicular to the plane of the page. What is the direction of the induced current in the coil?

2. A bar magnet held with its north & south poles along the east, west direction respectively is rapidly moved towards a circular coil held with its plane perpendicular to the direction of movement of bar magnet. Predict the direction of induced current in the circular coil.

3. Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side.What is direction of magnetic field?

4. Two circular coils A & B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.

5. State the rule to determine the direction of a magnetic field produced around a straight conductor – carrying current.

6. State the rule to determine the direction of force experienced by a current – carrying straight conductor placed in a magnetic field which is perpendicular to it.

7. When does an electric short circuit occur? 8. What is the function of an earth wire? Why is it necessary to earth metallic

appliances? 9. A current through a horizontal power line flows in east to west direction.

What is the direction of magnetic field at a point directly below it & at a point directly above it?

10. An electron enters a magnetic field at right angles to it as shown in the figure. The direction of force acting on the electron will be (a) to the right (b) to the left (c) out of the page (d) in to the page

Magnetic field Electron

11. Give two advantages of AC over DC.



12. Write the working principle of AC generator. 13. Which effect of electric current is utilized in the working of an electric fuse? 14. What will you do if you see a person coming in contact with a live wire? 15. Give two reasons why different electrical appliances in a domestic circuit are

connected in a parallel? 16. Why is a fuse wire made of a tin – lead alloy&not copper? 17. On what factors does the force experienced by a current –carrying conductor p

laced in a uniform magnetic field depend? 18. A magnet AB is broken into two pieces. What is the polarity of A,B,C& D? A B A B C D 19. A proton enters in a uniform magnetic field. Which of the following properties

will change (a) mass (b) speed (c) velocity (d) momentum. 20. Give the magnitude of magnetic field inside a long straight solenoid carrying

current? 21. Why does two magnetic field lines not intersect? 22. What is the frequency of A.C. in India? 23. Draw the pattern of magnetic field lines due to current carrying straight

conductor? 24. What is overloading? 25. Write the three ways to produce magnetic field? 26. What is electromagnetic induction (EMI)? 27. What is an electromagnet? What materials are used to make electromagnet? 28. Give some properties of a magnet. 29. What is Fleming's right hand rule? Explain. 30. Give some difference between bar magnet and electromagnet. 3 Marks: 1. What is the role of fuse, used in series with any electrical appliance? Why

should a fuse with defined rating not be replaced by one with a larger rating? 2. What is the difference between a direct current and an alternating current?

How many times does AC used in India change direction in one second? 3. An electrician assembling a household circuit uses a long thick copper wire

with green insulation and a short wire made up of copper-tin alloy. What are the two wires called? Mention the importance of each wire in an electric circuit. How are the two wires connected in the circuit?

4. What do you mean by (a) short circuit and (b) overloading? What are the safety precautions taken to avoid these problems in domestic electric circuits?

5. Explain different ways to induce current in a coil. 6. State Fleming’s right hand rule. How is this rule useful?



7. What is an armature? Mention the alternative methods adopted in commercial motors to enhance their power.

8. What is the use of a commutator? Name the component in an electric motor which acts as a commutator.

9. Why does a current-carrying conductor kept in a magnetic field experience force? On what factors does the direction of this force depend? Name and state the rule used for determination of direction of this force.

10. The magnetic field in a given region is uniform. Draw a diagram to represent it.

11. What is an electro-magnet? Draw a diagram showing an electro-magnet. 12. Draw the pattern of magnetic field lines of a current-carrying solenoid. What

does the pattern of field lines inside a solenoid indicate? Write one application of magnetic field of current-carrying solenoid.

13. What are the factors on which the magnetic field due to a current-carrying circular coil depends? Also explain the pattern of field lines produced in and around a circular coil.

14. Draw a sketch of the patten of field lines due to a (i) current flowing in a circular coil (ii) current carrying solenoid.

15. What is an electromagnet? What does it consist of? Name one material in each case which is used to make a (i) permanent magnet (ii) Temporary magnet.

16. Two circular coils A and B are placed close to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.

5 Marks: 1. With a labeled diagram, describe the construction and working of an electric

motor. What is the function of split ring commutator in a motor? 2. Explain the meaning of the word ‘electromagnetic’ and ‘induction’ in the term

electromagnetic induction. On what factors does the value of induced current produced in a circuit depend? Name and state the rule used for determination of direction of induced current. State one practical application of this phenomenon in every day life.

3. What is the magnitude of magnetic force per unit length on a wire carrying a current of 8A and making an angle of 30º with the direction of a uniform magnetic field of 0.15 T?

4. A 3.0 cm wire carrying a current of 10 A is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 0.27 T. What is the magnetic force on the wire?

5. a) Write principle of electric generator. b) Explain construction and working of generator. c) Draw labelled diagram of electric generator.



1 Mark 1. State the direction of the magnetic field inside the bar magnet . 2. Write relation between heat energy produced in a conductor when a potential difference V is

applied across its terminals and a current I flows through it for time t. 3. Define SI unit of resistivity.

4. If the charge on an electron be 1.61019 C, find the approximate number of electrons in 1C. 5. For same current flowing through a solenoid and a straight conductor, the magnetic field

produced by a solenoid is much stronger than the magnetic field produced by a straight current carrying conductor. State one reason to justify this statement

6. In an electric circuit, it is found that, all its components carry same current but the potential difference across each is different. Identify the type of combination in which these components are joined.

7. Name any two non-conventional sources of energy. 8. Name the volatile liquid boiled with the warm surface water of oceans for running ocean

thermal energy plants. 9. List two steps of energy transformation that take place in a thermal power plant. 10. Blowing wind carries kinetic energy. Mention the two factors that causes wind to blow . 11. Name the volatile liquid boiled with the warm surface water of oceans for running ocean

thermal energy plants. 12. Name any two fossil fuels.

3 Marks: 1. Explain whether an alpha particle (which is a positively charged particle) will experience any

force in a magnetic field if : (i)it is placed in the field at rest (ii)it moves in the magnetic field parallel to field lines (iii)it moves in the magnetic field perpendicular to field lines. 2. An electrical bulb is rated 40 W, 220 V. How many bulbs can be connected in parallel with

each other across the two wires of 220 V line if the maximum allowable current is 6 A ? 3. List three different situations in which the current in the circuit abruptly increases. What is the

name of these situations? How can we prevent the electric circuit and appliances from possible damage under these situations?

4. (a)What type of core should be put inside a current carrying solenoid to make an electromagnet ?

(b)List two ways by which strength of the magnetic filed of a current carrying solenoid to make an electromagnet be increased ?

5. Nikhil has set up a solar cooker in a box using a black painted aluminum sheet, a glass plate and a mirror. State the role of each item used in the solar cooker.

6. Calculate the resistance of a 1 km long copper wire of area of cross – section 2102 cm2. The resistivity of copper is 1.62108 ohm metre.

7. Explain whether an alpha particle (which is a positively charged particle) will experience any force in a magnetic field if :



(i)it is placed in the field at rest (ii)it moves in the magnetic field parallel to field lines (iii)it moves in the magnetic field perpendicular to field lines. 8. A circuit has a fuse of rating 5 A. What is the maximum number of 40 Watts (200 V) bulbs that

can be safely used in the circuit ? 9. Amit lives in Delhi and is much concerned about the increasing electricity bill of his house. He

took some steps to save electricity and succeeded in doing so. (i)Mention any two steps that Amit might have taken to save electricity. (ii)Amit fulfilled his duty towards the environment by saving electricity. How? (iii)Which alternative source of energy would you suggest Amit to use ? 10. Write any three limitations of using solar cooker for cooking food. 11. State Ohm’s law. Draw a circuit diagram to verify this law indicating the positive and negative

terminals of the battery and the meters. Also show the direction of current in the circuit. 12. A uniform magnetic field is directed vertically upwards. In which direction in this fieldshould

an – particle (which are positively charged particles) be projected so that it is deflected south ward? Name and state the rule you have used to find the direction in this case.

13. A magnetic compass needle is placed in the plane of the paper. In which plane would you place a straight current carrying conductor near this needle so that there is no change in the deflection of the compass? State the condition of the current carrying conductor in which the compass needle will show the maximum deflection. Justify your answer.

14. Anita lived with her parents in a joint family in which almost every member had an independent bathroom fitted with electric geysers. Anita persuaded her grandfather to replace these by fitting solar geyser on the roof and all agreed to this suggestion after hearing her arguments.

(a)List two values exhibited by Anita. (b)Explain how Anita succeeded in passing on these values to all members of her family . 15. (a)Why do electricians wear rubber hand gloves while working ? (b)What potential difference is needed to send a current of 5 A through the electrical appliance

having a resistance of 18 ? 16. A magnetic compass needle is placed in the plane of the paper. In which plane would you

place a straight current carrying conductor near this needle so that there is no change in the deflection of the compass? State the condition of the current carrying conductor in which the compass needle will show the maximum deflection. Justify your answer.

17. List the various factors on which the resistance of a cylindrical conductor depends. Write an expression relating these factors. How is resistance of a conductor different from its resistivity?

18. Sheelu was visiting her city after one year. Since during summers there were frequent power breakdown, she was a bit uncomfortable thinking about the unruly traffic in the city without traffic signals. But to her surprise, she found that all the traffic signals were working, inspite of the load shedding. She saw that all the traffic signals were powered by the solar cell panels. At one particular signals she saw that some naughty boys were trying to break the solar panel. She stopped them from doing so and explained them not to do so.

(a)State the value exhibited by Sheelu.



(b)Explain any two arguments in favour of using solar panels for running traffic signals for managing traffic.

19. State any two impacts on the environment caused due to increase in demand for energy. Suggest any two steps to reduce energy consumption.

20. V – I graphs for two conductors A and B are shown in the figure. Both of them are connected in parallel to a battery. Which of the two will produce more heat per unit time? Give justification for your answer.

21. For the current carrying solenoid as shown below, draw magnetic field lines and giving reason

explain that out of the three points A, B and C at which point the field strength is maximum and at which point it is minimum.

22. While going out with his mother one day, Ramesh observed that the date of pollution under

control certificate (PUC) of her mother’s two-wheeler scooter has expired. He advised her mother to get a new certificate as soon as possible. Ramesh’s mother was very impressed with him and got the pollution level checked immediately and obtained a ‘PUC’ certificate.

(i)Why did Ramesh show urgency in obtaining a ‘PUC’ certificate? (ii)Why was Ramesh’s mother impressed with him? (iii)Write one harmful effect of burning of fossil fuels other than air pollution. 23. Explain the term ‘geothermal energy’. How can it be exploited? Though it is economical yet it

is not harnessed in most of the countries. Why ? 24. Traffic jams, outside the school gate was a common sight since most of the students came on

their own cars. This became a topic for discussion on every P.T.A meeting. On one such P.T.A meeting, the principal pointed out the examples of four of their teachers who were car pooling for the past several years. She asked the parents also to adopt this method to sort out the problem.

(a)List two values shown by the teachers mentioned by the Principal. (b)Explain two advantages that will occur if more parents emulated the example of these

teachers. 25. (a)Define tidal energy. (b)Explain how is tidal energy harnessed and write one limitation of the use of tidal energy.

5 Marks: 1. a)Which is the better way to connect lights and other appliances in domestic circuit, series

connectionor parallel electrical connection ? Justify your answer.



(b)An electrician has made electric circuit of a house in such a way that if a lamp gets fused in a room of the house, all the lamps in other rooms of the house stop working. What is the defect in this type of circuit wiring ? Give reason.

2. (a)Identify the effect of the electric current which is utilized in the working of an electric fuse. (b)How is fuse connected in a household circuit ? Give reason for your answer. (c)Draw a schematic labelled diagram of a domestic electric circuit which has a provision of a

fuse, a meter, a bulb and a switch. 3. A student fixes a sheet of white paper on a drawing board. He places a bar magnet in the

centre of it. He sprinkles some iron filings uniformly around the bar magnet. Then he taps the board gently.

Now answer the following questions : (i)What does the student observe ? Draw a diagram to illustrate your answer. (ii)Why do the iron filings arrange in such a pattern ? (iii)What does the crowding of the iron filings at the ends of the magnet indicate ? 4. What do you mean by heating effect of electric current ? Explain the production of heat in a

resistor by flow of electric current through it. Name two devices based on heating effect of current.

5. (a)Describe an activity to determine the direction of magnetic field produced by a current carrying straight conductor. Also show that the direction of the magnetic field is reversed on reversing the direction of current.

(b)An -particle, (Which is a positively charged particle)enters, a uniform magnetic field at right angles to it as shown below. Stating the relevant principle explain in which direction will this -particle move ?

6. (a)What is meant by the series combination and parallel combination of resistances?

(b)In the circuit diagram given below five resistances of 5, 20,15, 20 and 10 are connected as given in figure to a 6 V battery.

Calculate : (i)Total resistance in the circuit. (ii)Total current flowing in the circuit. 7. (a)What is a magnetic field ? How is the direction of magnetic field at a place determined ? (b)State the rule for the direction of magnetic field produced around a current carrying straight

conductor. Draw the pattern of this field. 8. Give reason for the following: (i)An electric bulb is not filled with air but is filled with argon or nitrogen. (ii)The filament type electric bulbs are not power efficient. (iii)The coils of heating devices are made of alloys rather than pure metals. (iv)Copper and aluminium wires are usually used for electricity transmission.



(v)The current that makes the heater element red hot only slightly warms the connecting wire leading to the heater.

8. For the parallel combination of resistors establish the relation :

1 2 3

1 1 1 1R R R R

5 1 1

where the symbols have their usual meanings. Find the resistance between A and B in the following network.

9. The magnetic field lines associated with current carrying straight conductor is in anticlockwise

direction. If the conductor was held horizontally along east-west direction, what is the direction of current through it ? Explain it with the help of diagram. Name and state the rule applied to determine the direction of magnetic field. If the conductor is held vertically and current flows from north to south, what will be the direction of magnetic field lines. Draw diagram.

10. What is meant by electric circuit ? Why does electric current start flowing in a circuit the moment circuit is complete ? When do we say that the potential difference across a conductor in a circuit is 1 volt ?

Calculate the potential difference between the two terminals of a battery if 12 joules of work is done in transferring 2 coulombs of charge.

11. (a)Which is the better way to connect lights and other appliances in domestic circuit, series connection or parallelelectrical connection ? Justify your answer.

(b)An electrician has made electric circuit of a house in such a way that if a lamp gets fused in a room of the house, all the lamps in other rooms of the house stop working. What is the defect in this type of circuit wiring ? Give reason.

12. (a)Identify the effect of the electric current which is utilized in the working of an electric fuse. (b)How is fuse connected in a household circuit ? Give reason for your answer. (c)Draw a schematic labelled diagram of a domestic electric circuit which has a provision of a

fuse, a meter, a bulb and a switch. 13. What are magnetic field lines ? List three characteristics of these lines. Describe in brief an

activity to study the magnetic field lines due to a current carrying circular coil. 14. (a)Name an instrument that measures electric current in a circuit. Define unit of electric

current. (b)What are the following symbols mean in an electric circuit.

(i) (ii) (c) Draw a closed circuit diagram consisting of 0.5 m long nichrome wire XY, an ammeter, a

voltmeter, four cells of 1.5 V and a plug key. 15. (a)Why is it necessary to earth the metallic electric appliances ? (b)Explain what is short circuiting and over loading. (c)What is the usual capacity of fuse wire in the line for



(i)lights and fans ? (ii)Appliances of 2 kw or more power ? 16. State the factors on which the resistance of a metallic wire depends. Define the term resistivity

and derive its SI unit. A wire of length 1 metre and radius 0.02 cm has a resistance of 5.0 ohms. Calculate the

resistivity of the material of the wire. 17. State Ohm's law. Draw graph between V and I for a metallic conductor. Define resistivity

with unit. What is the effect of temperature on the resistivity of metals? 18. (a)Explain what is the difference between a direct current and an alternating current.

Write one important advantage of using alternating current. (b)An air conditioner of 2 kW is used in an electric circuit having a fuse of 10 A rating. If the

potential difference of the supply is 220 V, will the fuse be able to withstand, when the air conditioner is switched on ? Justify your answer.

19. List four factors on which the resistance of a conductor depends. The resistivities of some substances are given below.

Material A B C D E

Resistivity(m)

1.6108 6.4108 10108 96108 100106

Answer the following questions in relation to them giving justification for each: (i)Which material is best for making connecting cords? (ii)Which material do you suggest to be used in heater elements in heating devices? (iii)You have two wires of same length and same thickness. One is made of material A and

another of material D. If the resistance of wire made of A is 2 , what is the resistance of the other wire?

Short Answer Type Questions: 1. State how the image position changes in myopia and hypermetropia, as compare to a normal

human eye. 2. A person is able to see objects clearly only when these are lying at distances between 50 cm

and 300 cm from his eye. Identify the kind of defects of vision he is suffering from. Give reason for your answer.

3. After examining eyes of a person doctor tells him that he has cataract ? State what happens to the eye in such a state ? Suggest one method of its correction.

The near point of a hypermetropic eye is at 75 cm from the eye. What is the nature of lens required by him to read clearly a book held at 25 cm from the eye ?

4. Sushil went to an eye specialist for check up. He prescribed him to use spectacle lens of 0.5D power.

(a) Name the defect of vision he is suffering from. (b) Find the focal length of spectacle lens?

5. Sushil went to an eye specialist for check up. He prescribed him to use spectacle lens of 0.5D power.

(a) Name the defect of vision he is suffering from.



(b) Find the focal length of spectacle lens?

6. A person is able to see objects clearly only when these are lying at distances between 50 cm and 300 cm from his eye. Identify the kind of defects of vision he is suffering from. Give reason for your answer.

7. A person is not able to see distinctly the objects placed beyond 90 cm from him. Giving reason identify the defect in his eye. Determine the nature, of lens used to correct the defect.

8. A person is not able to see distinctly the objects placed beyond 2 m from him. Giving reason identify the defect in his eye. Write the nature of lens used to correct the defect.

9. A person is not able to see distinctly the objects placed beyond 90 cm from him. Giving reason identify the defect in his eye. Determine the nature, of lens used to correct the defect.

3 Marks

1. Explain the terms related to human eye : (i) Power of Accommodation (ii) Far point (iii) Near point 2. (a) Calculate the distance at which an object should be placed in front of a convex lens of focal

length 10 cm to obtain a virtual image of double its size. (b) In the above given case find the magnification if image formed is real. Express it in terms of relation

between ‘v’ and ‘u’.

3. Explain the terms related to human eye : (i) Power of Accommodation (ii) Far point (iii) Near point 4. Explain the terms aperture, optical centre and principal axis of a spherical lens with the help of

diagram. 5. Explain Power of Accommodation. Explain in brief the near and the far point of an eye and

give their values. 6. Draw a ray diagram to show refracted ray when ray incident on a convex lens is : (a) parallel to principal axis (b) passing through optical centre of lens (c) passing through its focus lens. 7. (a) Name the part of eye that : (i) Controls the amount of light entering into eye (ii) Regulates the size of the passage through which light enters (b) Why are we not able to see immediately after we enter a dark hall from a lighted place ?

8. Explain the terms aperture, optical centre and principal axis of a spherical lens with the help of diagram.

9. Name the four parts labelled as 1, 2, 3 and 4 in the given diagram of human eye. State the function of pupil of an eye.



10. While performing an experiment in the laboratory a student covered upper half of the convex lens with the help of a black paper.Will he observe an image of the complete object ? Draw a ray diagram to justify your answer. How will this image differ from the one obtained without covering the lens ? Give reason for your answer.

11. (a) Define power of accommodation of the eye. (b) Why does the power of accommodation of an eye decreases with age ? Explain. 12. Complete the ray diagram given below and write the nature of image in the two cases.

13. (a) Mention the role of crystalline lens in the human eye. (b) How does the focal length of the eye lens change when we shift looking from a nearby object to a

distant object ?

14. A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 10 cm. The distance of the object from the lens is 15 cm. Find the nature, position and size of the image. Also find its magnification.

15. (a) Name the part of eye that : (i) Controls the amount of light entering into eye (ii) Regulates the size of the passage through which light enters (b) Why are we not able to see immediately after we enter a dark hall from a lighted place ?

16. A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 10 cm. The distance of the object from the lens is 15 cm. Find the nature, position and size of the image. Also find its magnification.

17. Explain the terms related to human eye : (i) Power of Accommodation (ii) Far point (iii) Near point 18. A concave lens has focal length of 20 cm. At what distance from the lens should a 5 cm tall

object be placed so that it forms an image at 15 cm from the lens ? Also calculate the size of the image formed.

5 Marks

1. Refractive indices of four media A, B, C and D are given below :

Medium Refractive index

A 1.33

B 1.44

C 1.55



D 1.66

(a) In which of the given media is the speed of the light maximum and minimum ? (b) Which of them is the most optically dense and which one is the least optically dense

medium ? (c) Calculate refractive index of medium B with respect to medium C. Give reasons for your answers.

2. Describe how you will trace the path of a ray of light passing through a glass prism. Draw a detailed diagram and label the rays and angles.

3. Draw ray diagrams showing the image formation by a concave mirror when an object is placed :

(a) between pole and focus of the mirror (b) between focus and centre of curvature of the mirror (c) at the centre of curvature of the mirror (d) a little beyond the centre of curvature of the mirror (e) at infinity 4. (a) Write the laws of refraction of light. What is the ratio of the sine of the angle of incidence to

the sine of the angle of refraction commonly known as ? (b) What is meant by statement that refractive index of diamond is 2.42 ? If the velocity of light in air is

8 13 10 ms , find velocity of light in diamond ?

5. A beam of white light falling on a glass prism gets split up into seven colours marked 1 to 7 as shown in the diagram.Redraw this diagram on the answer sheet and mark these seven colours. A student made a statement that the colour at position marked 5 and 3 are similar to the colour of the sky and colour of gold metal respectively. Is the above statement made by the student correct or incorrect ? Justify.

Appraise the cause of dispersion, when white light enters a glass prism and write the least and most dispersed colour.

6. A student has three concave mirrors A, B, C of focal lengths 20 cm, 15 cm and 10 cm

respectively. For each concave mirror he performs the experiment of image formation for three values of object distance of 30 cm, 10 cm and 20 cm.

7. Giving reason answer the following : (a) For the three object distances identify the mirrors which will form an image equal in size to

that of object.



(b) Out of the three mirrors identify the mirror which would be preferred to be used for shaving purpose.

(c) For the mirror B draw ray diagram for image formation for any two given values of object distance.

8. (a) Define refraction of light. (b) A ray of light is incident on the interface separating diamond and water. Given that the

refractive index of diamond and water with respect to air are 2.42 and 1.33 respectively. Complete the diagram by showing refracted ray and mark angles of incidence and refraction.

(c) Calculate speed of light in water. (given that velocity of light in air is 8 13 10 ms 9. (a) Explain with the help of a labelled diagram how can a combination of two prisms be used

so that an incident white light emerge out of second prism as white light. (b) Name the scientist who first performed this activity.

(c) Explain the term spectrum in brief. 10. State the relation between object distance, image distance and focal length of a concave or

convex mirror. A concave mirror produces two times magnified real image of an object at 10 cm from it. Find the position of the image.

11. (a) List two characteristics of refraction of light. (b) Define absolute refractive index. (c) Name the physical quantity with which refractive index of a medium can be related. (d) What is meant by the statement that refractive index of water is 1.33 ?

12. (a) Define dispersion of light. How is scattering of light different from its dispersion ? Give one example of natural phenomenon based oneach of these.

(b) A beam of light consisting of red, blue and yellow is incident on theprisms as shown below. Complete the diagram to show refractedand emergent ray

13. An object is placed at 15 cm from a concave mirror of focal length 10 cm. Find the position and

nature of image formed. Draw ray diagram to illustrate the formation of image. (not to scale). 14. A pencil partly immersed in water appears to be bent at water surface, explain it with the help

of a labelled diagram. State whether the bending of pencil will increase or decrease if water is replaced by another liquid which is optically more dense than water, explain.

15. Describe how you will trace the path of a ray of light passing through a glass prism. Draw a detailed diagram and label the rays and angles.

16. An object is placed at 5 cm from a concave mirror of focal length 10 cm. Find the position and nature of image formed. Draw ray diagram to explain the formation of image. (not to scale).



17. (a) Explain the term refraction of light. (b) Letters written on a paper when seen through a rectangular glass slab appear to be raised.

Explain this phenomenon with the help of a ray diagram. (c) Light enters from air into diamond which has a refractive index of 2.42. Calculate the speed of light

in diamond. The speed of light in air is 8 13 10 ms

18. (a) Define angle of deviation. Why do different components of white light split up into spectrum when it passes through a triangular glass prism ?

(b) What is rainbow ? State the two necessary conditions for the formation of rainbow in the sky.

19. (a) A dentist uses a mirror in front of a decayed tooth at a distance of 4 cm from the tooth to get a 4 times magnified image . Use mirror formula to find the focal length and nature of mirror used. What is the nature of image.

(b) A mirror produces a magnification of 3. When an object is placed at a distance of 20 cm from the mirror, find the position of image.

20. (a) Write the laws of refraction of light. What is the ratio of the sine of the angle of incidence to the sine of the angle of refraction commonly known as ?

(b) What is meant by statement that refractive index of diamond is 2.42 ? If the velocity of light in air is 8 13 10 ms , find velocity of light in diamond ?

21. An object of height 2 cm is placed at a distance of 15 cm from a concave mirror of focal length 10 cm. Find the size, nature and position of image formed.

22. With the help of a labelled diagram, state and explain the laws of refraction of light. What is the refractive index of a substance if light travells through air at 3x 810 m/s. On entering in another medium its speed becomes at 2x 810 m/s. Calculate the refractive index of other medium.

23. Explain how rainbow is formed. Draw a labelled diagram showing the different phenomena of light which occur in the tiny water droplets after rain shower to produce a rainbow.

24. A student has three concave mirrors A, B, C of focal lengths 20 cm, 15 cm and 10 cm respectively. For each concave mirror he performs the experiment of image formation for three values of object distance of 30 cm, 10 cm and 20 cm.

Giving reason answer the following : (a) For the three object distances identify the mirrors which will form an image equal in size to

that of object. (b) Out of the three mirrors identify the mirror which would be preferred to be used for

shaving purpose. (c) For the mirror B draw ray diagram for image formation for any two given values of object

distance. 25. (a) List the colours observed in a spectrum through a prism in the increasing order of their

deviation through prism. (b) With the help of a diagram explain how dispersed light can be recombined to produce white light.

26. An object is placed at infinity from a concave mirror of focal length 10 cm. Find the position and nature of image formed. Draw ray diagram to show the formation of image. (not to scale).



CHEMISTRY 1. Chemical Reactions and Equations

1 Mark: 1. Why do fire flies glow at night? 2. Why do we store silver chloride in dark coloured bottles? 3. What happens when the milk is left at room temperature during summer? 4. Write a chemical equation when magnesium is burnt in air to give magnesium

oxide. 5. A substance under goes chemical reactions to produce simpler products what

type of reaction is this? 6. Why do copper vessels lose their shine when exposed to air? 7. Which gas is produced by the action of dilute hydrochloric acid on zinc

granules? 8. Fe2O3 + 2Al →Al2O3 + 2Fe The above reaction is an example of which type of reaction. 9. Name the type of reaction in which energy is absorbed. 10. Why does the colour of copper sulphate solution change when an iron nail

dipped into it? 11. Give an example of decomposition reaction which proceeds by absorbing electric energy. 12. Why do we balance the chemical equation? 13. What changes do you observe in the iron nails and colour of copper

sulphatesolution, if iron nails are dipped in CuSO4 solution for 15 minutes ? 14. Identify the chemical change: A) Melting of ice B) conversion of milk into curd. 15. Why is respiration considered an exothermic reaction? 16. Why does copper vessel lose shine when exposed to air? 17. Potato chips manufacturers fill the packet of chips with nitrogen gas. Why? 18. Why we store silver chloride in dark coloured bottles? 19. Write a chemical equation of double displacement reaction. 20. N2 + 3H2 → 2NH3, name the type of reaction. 21. What happens when milk is left open at room temperature during summers? 22. What happens when quick lime is added to water?

2 Marks: 1. When magnesium ribbon is burnt in air, a product is formed. State the type of

chemical change and name of the product formed? 2. Give one example of each: a) Chemical reactions evolution showing of gas.



b) Change in substances colour during a chemical reaction. 3. If small amount of ferrous sulphate is heated in hard glass tube? a) Write the chemical equation. b) What type of the reaction is taking place? 4. What happen when zinc strips is dipped in CuSO4 solution? 5. in electrolysis of water a) Name the gas collected at cathode and anode b) Why is volume of one gas collected at one electrode is double of another? 6. In the reaction CuO(s)+ H2 (g) ------> Cu (s) + H2O (g) a) Name the oxidised substance. b) Name the reduced substance. 7. Compound "X" decomposes to form compound "Y” and CO2 gas. compound

"Y" is used in manufacturing of cement. a) Name the compound "X" and "Y". b) Write the chemical equation for the reaction. 8. A metal strip "x" is dipped in blue coloured salt solution YSO4. After sometime

a layer of metal "y" is formed on metal strip "X". Metal "X" is used in galvanization where as metal "Y" is used for making electric wires.

a) What could be metal "X" and "Y”? b) Name the metal salt YSO4.

9. Give reasons: a) White silver chloride turns grey in sunlight. b) Brown coloured copper powder on heating in air turns into black coloured

substance. 10. What is redox reaction? Write down a chemical reaction representing it. 11. What change do you observe in the iron nails and colour of copper sulphate

solution, if iron nails are dipped in CUSO4 solution for 15 minutes? 12. Write the balanced chemical equation for the following reaction and identify

the type of reaction in each case. a) Ethanol was warmed with ethanoic acid to form ethyl acetate in the

presence of concentrated H2SO4. b) Ethane is burnt in the presence of oxygen to form carbon dioxide, water and

release heat and light. 13. Complete the missing components/ variables given as "x" and "y" in the

following reaction. a) Pb(NO3)2 (aq) + 2K (aq) ----> PbI2 (x) + 2KNO3 (y) b) Cu(s) + 2AgNO3(aq) ---->Cu (NO3)2 (aq) + x(s) 14. Zinc liberates hydrogen gas when reacted with dilute HClwhereas copper does

not, explain why?



15. On adding a drop of barium chloride solution to an aqueous solution of sodium sulphate, white precipitate is obtained

a) Write a balanced chemical equation of the reaction involved. b) What other name can be given to this precipitation reaction? 16. You are provided with two containers made up of copper and aluminium. You

are provided with solution of dil.HCl, dil.HNO3, ZnCl2 and H20. In which of the above containers this solution can be kept?

17. A metal salt "MX" when exposed to light splits into form metal "M" and gas "X2". Metal "M" is used to make ornaments whereas gas "X2" is used in making bleaching powder. The salt "MX" used in black and white photography.

a) Identify the metal "M" and gas "X". b) Identify the "MX". 18. What are two conditions which promotes corrosion? 19. Identify the reducing agent in the following reaction? a) 4NH3 + 5O2 ----> 4NO + 6H20 b) H20 + F2 ----> HF + HOF 20. Grapes hanging on the plant do not ferment but after being plucked from the

plants can be fermented. Under what conditions do these grapes ferment? Is it a chemical (or) physical change?

21. What is the colour of ferrous sulphate crystals? How does this colour change after heating?

22. When a solution of potassium iodide is added to a solution of lead nitrate in a test tube a reaction takes place?

23. Why should magnesium ribbon be cleaned before burning in air? 24. A student added a few pieces of zinc into dil.H2SO4 taken in a test tube.

Suddenly evaluation of gas occurs. What gas evolved? 25. While performing an experiment, a student adds Na2SO4 solution to a

colourless solution .A white precipitate is immediately formed and is insoluble in dil.HCl. What is the colourless solution and the precipitate formed?

26. Take dil.H2SO4 in a test tube and put few zinc granules into the test tube. What is your observation?

27. When a solution of potassium iodide is added to a solution of lead nitrate in a test tube a reaction takes place.

a) What type of reaction is this? b) Write a balanced chemical equation to represent it. 28. When NaOH is added to zinc sulphate solution, a precipitate is formed which

is soluble in excess of NaOH. What is the precipitate obtained and the colour of the precipitate?

29. Give the reason for the following: a) Aluminium oxide is considered amphoteric oxide. b) Some alloys are called amalgam.



30. Metal compound "A" reacts with dil.HCl to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.

3 Marks: 1. Identify the reducing agent in the following reactions (a) 4NH3 + 5O2↑→ 4NO + 6H2O (b) H2O + F2 ↑→HF + HOF (c) Fe2O3 + 3CO ↑→2Fe + 3CO2 (d) 2H2 + O2↑→2H2O 2. Write the balanced chemical equations for the following reactions (a) Sodium carbonate on reaction with hydrochloric acid in equal molar

concentrations gives sodium chloride and sodium hydrogen carbonate. (b) Sodium hydrogen carbonate on reaction with hydrochloric acid gives

sodium chloride, water and liberates carbon dioxide. (c) Copper sulphate on treatment with potassium iodide precipitates cuprous

iodide (Cu2I2), liberates iodine gas and also forms potassium sulphate. 3. A solution of potassium chloride when mixed with silver nitrate solution, an

insoluble white substance is formed. Write the chemical reaction involved and also mention the type of the chemical reaction?

4. A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.

(a) Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.

(b) Name the black substance formed and give its chemical formula 5. What is a balanced chemical equation? Why should chemical equations be

balanced? 6. Translate the following statements into chemical equations and then balance

them. (a) Hydrogen gas combines with nitrogen to form ammonia. (b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (c) Barium chloride reacts with aluminiumsulphate to give aluminium chloride

and a precipitate of barium sulphate. 7. Write the balanced chemical equation for the following and identify the type of

reaction in each case. (a)Potassium bromide (aq) + Barium iodide (aq) → Potassium iodide (aq)

+Barium bromide(s) (b) Zinc carbonate (s) → Zinc oxide (s) + Carbon dioxide (g) (c) Hydrogen (g) + Chlorine (g) → Hydrogen chloride (g) 8. Why is respiration considered an exothermic reaction? Explain.



9. Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions

10. What is the difference between displacement and double displacement reactions? Write equations for these reactions.

11. In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved

12. Explain the following in terms of gain or loss of oxygen with two examples each.

(a) Oxidation (b) Reduction 13. A shiny brown-coloured element ‘X’ on heating in air becomes black in colour.

Name the element ‘X’ and the black coloured compound formed. 14. Oil and fat containing food items are flushed with nitrogen. Why? 15. Explain the following terms with one example each. (a) Corrosion (b) Rancidity 16. Write down the balanced chemical equations for the following reactions. a) Zinc Carbonate(s) →Zinc Oxide(s) + Carbon Dioxide(g) b) Aluminium(s) + Chlorine(g)→ Aluminium Chloride(s) c) Magnesium(s)+Water(l) →Magnesium Hydroxide(l)+Hydrogen(g) 17. Choose combination, displacement and double displacement reactions out

ofthe given reactions. i) MnO2(s) + 4HCl(l) →MnCl2(s) + Cl2(g) + 2H2O(l) ii) CaO(s) + CO2 (g) →CaCO3(s) iii) 2AgCl(s) →2Ag(s) + Cl2 (g) 18. What is redox reaction? Write down a chemical reaction representing it. 19. in electrolysis of water: (a) Name the gas collected at cathode and anode. (b) Why is volume of one gas collected at one electrode is double of another? (c) Why are few drops of dil. H2SO4 added to water? 20. in the reaction CuO (s) + H2 (g) → Cu(s) + H2O (g) (a) Name the oxidized substance. (b) Name the reduced substance. (c) Name the oxidizing agent. 21. Give reasons: (a) White silver chloride turns grey in sunlight. (b) Brown coloured copper powder on heating in air turns into blackcoloured

substance. 22. Compound ‘X’ decomposes to form compound ‘Y’ and CO2 gas. Compound Y

isused in manufacturing of cement.



(a) Name the compounds ‘X’ and ‘Y’. (b) Write the chemical equation for this reaction. 23. A metal salt MX when exposed to light splits upto to form metal M and gas X2. Metal M is used to make ornaments whereas gas X2 is used in making bleaching powder. The salt MX is used in black & white photography. (a) Identify the metal M and gas X2. (b) Identify MX. (c) Write down the chemical reaction when salt MX is exposed to sunlight. 24. A metal strip X is dipped in blue coloured salt solution YSO4. After some time

a layer of metal ‘Y’ is formed on metal strip X. Metal X is used in galvanization whereas metal Y is used for making electric wires.

(a) What could be metal ‘X’ and ‘Y’? (b) Name the metal salt YSO4. (c) What type of chemical reaction takes place between X and YSO4? Write the

balanced chemical equation.

5 Marks: 1. On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper

oxide (black), oxygen gas and a brown gas X is formed (a) Write a balanced chemical equation of the reaction. (b) Identity the brown gas X evolved. (c) Identity the type of reaction. (d) What could be the pH range of aqueous solution of the gas X? 2. Give the characteristic tests for the following gases (a) CO2 (b) SO2 (c) O2 (d) H2 3. What happens when a piece of (a) zinc metal is added to copper sulphate solution? (b) aluminium metal is added to dilute hydrochloric acid? (c) silver metal is added to copper sulphate solution? Also, write the balanced chemical equation if the reaction occurs 4. What happens when zinc granules are treated with dilute solution of H2SO4,

HCl, HNO3, NaCl and NaOH, also write the chemical equations if reaction occurs.

5. On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained.

(a) Write a balanced chemical equation of the reaction involved (b) What other name can be given to this precipitation reaction?



(c) On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?

6. You are provided with two containers made up of copper and aluminium. You are also provided with solutions of dilute HCl, dilute HNO3, ZnCl2 and H2O. In which of the above containers these solutions can be kept?

7. Balance the following chemical equation and identify the type of reaction they represent a) KClO3 →KCl + O2 b) NH3 + O2 →NO + H2O c) Na2O + H2O →NaOH d) Na + H2O →NaOH + H2 e) FeCl3 + NaOH →Fe(OH)3 + NaCl. 8. Define various types of chemical reactions. Write one chemical equation for

each type. 9. White wash was being done at Mukesh’shouse.Mukesh saw that the

painteradded quick lime to drum having water. Mukesh touched outer surface of drum, it is unbelievably hot.

(a) Write the chemical equation for above reaction. (b) What type of reaction is it? (c) What is utility of this reaction? 10. What types of reactions are represented by following? (a) CaCO3 → CaO + CO2 (b) 2Ca + O2 → 2CaO (c) Pb + CuCl2 → PbCl2 + Cu (d) 2FeSO4 → Fe2O3 + SO2 + SO3 (e) Na2SO4 + BaCl2 → BaCl2 + 2NaCl 11. Balance the following equations: (a) H2 + O2 → H2O (b) MnO2 + HCl → MnCl2 + H2O + Cl2 (c) Pb(NO3)2 → PbO + NO2 + O2 (d) AgNO3 + NaCl → AgCl + NaNO3 (e) Ca(OH)2 + HNO3 → Ca(NO3)2 + H2O 12. Write down the balanced chemical equation for the following: (a) Silver chloride is decomposed in presence of sunlight to give silver

andchlorine gas. (b) Calcium oxide reacts with water to give lime water. (c) Sodium hydroxide reacts with hydrochloric acid to give sodium chlorideand

water. (d) Die hydrochloric acid is added to copper oxide to give green colouredcopper

chloride and water. (e) Solution of barium chloride and sodium sulphate in water reacts to give

insoluble barium sulphate and solution of sodium chloride.



2. Acids, Bases and Salts 1 Mark: 1. Two solution have pH number 4 and 9 respectively which solution has more

H+ ion concentration? 2. Why should cured and sour substances not be kept in brass and copper

vessel? 3. What is the chemical name of bleaching powder? 4. Write down the molecular formula for one strong and one weak acid. 5. Explain why plaster of Paris should be stored in a moisture proof container? 6. Name the gas evolved when dil. sulphuric acid acts on sodium carbonate. 7. What is the use of common salt in soap industry? 8. What do you observe when a burring candle is brought near the test tube

containing hydrogen gas? 9. Name the indicator used to measure pH values over the whole range. 10. Write the formula of washing powder. 11. Write two physical properties of an acid 12. Complete the reaction CaCO3 + H2O name the products formed. 13. A test tube contains solution of NaOH and Phenolphthalein. Why the colourof

the solution changes when HCl in added to it. 14. Identify the type of reaction H X + M OH MX + HOH 15. Why all bases are not alkalies but all alkalis are bases? 16. Name the acid present in ant sting. 17. What happens when egg shell is added to nitric acid? 18. Name a salt which does not contain water of crystallization. 19. Name two constituents of baking powder. 20. What is the pH of gastric juices released during digestion? 21. Which solution is used to dissolve gold? 22. How will you test a gas which is liberated when HCl acid reacts with an active

metal? 23. Why does flow of acid rain water into a river make the survival of aquatic life

in the river difficult? 24. When conc. acid is added to water, whether the process is exothermic or

endothermic? 25. Which by-product of chlor-alkali process is used for manufacturing bleaching

powder? 26. Why does bleaching powder smell strongly of chlorine and does not dissolve

completely in water? 27. Hold one moist and one dry strip of blue litmus paper over dry HCl acid gas.

Which strip will turn red and why?



28. What is Plaster of Paris? 29. What is the role of toothpastes in preventing cavities? 30. Explain why sour substances are effective in cleaning copper vessels? 31. How is Plaster of Paris obtained from gypsum? 32. How washing soda is prepared from baking soda? 33. What is the reaction called when an acid reacts with base to produce salt and

water? Give example also. 34. Why pickles and curd are not stored in copper and brass utensils? 35. Though the compounds such as glucose and alcohol have hydrogen atoms in

their molecule, yet they are not categorized as acids. Why? 36. Why does the flow of acid rain water into a river make the survival of aquatic

life in the river difficult? 37. Why should water be never added drop wise to concentrated sulphuric acid? 38. Write balanced chemical equations for the reactions taking place when dry

blue 39. Crystals of copper sulphate are dropped into concentrated sulphuric acid. 40. What is the role of tartaric acid in baking powder? 41. There are two jars A and B containing food materials. Food in jar A is 42. Pickled with acetic acid while B is not. Food of which jar will stale first? 43. If soil is acidic which compound would you spread to treat the soil? 44. Write two observations you make when quick lime is added to water. 45. Name the acids present in the following food stuffs which attribute to a sour

taste to them (a)Vitamin C tablet (b)Sour milk 46. What does pH stand for? What does pH scale indicate? 47. Sweet tooth may lead to tooth decay. Explain, why? What is the role of tooth

paste in preventing cavities? 48. How does turmeric change its colour in an alkaline medium? 49. What happens when an acid is dissolved in water? 50. What is a hydronium ion? How is it formed? 2 Marks: 1. Why sour substances are effective in cleaning copper vessels? 2. A white powder is added while baking breads and cakes to make them soft

and fluffy. What is the name of the powder? What are it's main ingredients? 3. Hold one moist and one dry strip of blue litmus paper over dry HCl acid gas.

Which strip will return red and why? 4. On passing excess CO2 through lime water, if first turns milky and then

becomes colourless. Explain why and write chemical equation.



5. While constructing a house, a builder can select the marble flooring and marble top for kitchen where vinegar and juices of lemon, tamarind etc. are more often used for cooking. Will you agree to this selection and why?

6. Why metallic oxides are called basic oxides and non-metallic oxides are called acidic oxides?

7. What will happen when excess of carbon dioxide is passed through lime water?

8. Salt "A" commonly used in bakery products on heating gets converted into another salt "B" which itself is used for removal of hardness of water and a gas "C" is evolved. The gas "C" was passed through lime water turns with milky. Identify A,B and C.

9. In one of the industrial process used for manufacture of NaOH, a gas "X" is formed as by product. The gas “X” reacts with lime water to give a compound "Y" which is used as a bleaching agent in chemical industry. Identify "X" and "Y" giving the chemical equation of the reaction involved.

10. How will you test a gas which is liberated when HCl acid reacts with an active metal?

11. Why does a milkman add a small amount of baking soda to fresh milk to shift the pH of fresh milk from 6 to slightly alkaline?

12. What happens when baking soda is heated? 13. What will be the action of the following substances on litmus paper? Dry HCl gas, Moistened NH3 gas, Lemon juice, carbonated soft drink, curd,

Soap solution 14. A student prepared solutions of (i) an acid and (ii) a base in two separate

beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?

15. How would you distinguish between baking powder and washing soda by heating?

16. When zinc metal is treated with a dilute solution of a strong acid, a gas is evolved, which is utilised in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of the reaction involved and also write a test to detect the gas formed.

17. A metal carbonate X on reacting with an acid gives a gas which when passed through a solution Y gives the carbonate back. On the other hand, a gas G that is obtained at anode during electrolysis of brine is passed on dry Y; it gives a compound Z, used for disinfecting drinking water. Identity X, Y, G and Z.

18. A sulphate salt of Group 2 element of the Periodic Table is a white, soft substance, which can be moulded into different shapes by making its dough. When this compound is left in open for some time, it becomes a solid mass and cannot be used for moulding purposes. Identify the sulphate salt and why does it show such a behaviour? Give the reaction involved.



19. Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. In which test tube will the fizzing occur more vigorously and why?

20. A milkman adds a very small amount of baking soda to fresh milk. (a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline? (b) Why does this milk take a long time to set as curd? 21. A substance ‘X’ used in the kitchen for mating tasty crispy pakoras and is also

an ingredient of antacid. Name of the substance “x” a) How does ‘X’ help to make cakes and bread soft and spongy. b) Is the PH value of solution of ‘X’ is lesser than (or) greater than 7.0?

22. A yellow powder x gives a pungent smell if left open in air. It is prepared by the reaction of dry compound Y with chlorine gas. It is used for disinfection drinking water. Identify X is Y and write the reaction involved.

23. A student heated a few crystals of copper sulphate in a dry boiling tube. a) What will be the colour of the CuSo4 after heating? b) Will you notice water droplets in boiling tube? 24. A dry pellet of common base ‘B’ when kept in oven observes moisture and turns

sticky. The compound is also by product of chloralkali process. Identify what type of reaction occurs when ‘B’ is treated with an acidic oxide? Write the balanced.

25. When a metal carbonate X on reacting with an acid gives a gas which when passed through a solution Y gives the carbonate back. On the other hand a gas ‘G’ that obtained at anode during electrolysis of brine in passed on dry ‘Y’ it gives acompound Z, used for disinfecting drinking water. Identify X, Y, G& Z.

26. When dilute HCl is added to granulated zinc placed in a test tube, the observation made is

a) The surface of the metal turns shinning b) The reaction mixture is observed. 27. What is dilute? Why carry must be taken while mixing concentrated nitric acid

or H2SO4 with water? 28. Name one natural source each of the following acid a) Citric acid b) Oxalic acid c) Lactic acid d) Tartaric acid 29. How is the concentration of Hydronium ions (H30+) effected when a solution of

an acid is diluted? 30. Under what soil condition do you think a farmer would treat the soil of his

fields with quick lime (or) slaked lime (or) chalk (calcium carbonate)?



3 Marks: 1. Match the acids given in Column (A) with their correct source given in Column

(B).

2. Name the acid present in ant sting and give its chemical formula. Also give the

common method to get relief from the discomfort caused by the ant sting. 3. A student prepared solutions of (i) an acid and (ii) a base in two separate

beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?

4. What are strong and weak acids? In the following list of acids, separate strong acids from weak acids.

Hydrochloric acid, citric acid, acetic acid, nitric acid, formic acid, sulphuric acid

5. Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1,11, 7 and 9, respectively. Which solution is

(a) neutral? (b) Strongly alkaline? (c) Strongly acidic? (d) Weakly acidic? (e) Weakly alkaline? Arrange the pH in increasing order of hydrogen-ion concentration 6. Equal lengths of magnesium ribbons are taken in test tubes A and B.

Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. In which test tube will the fizzing occur more vigorously and why?

7. A milkman adds a very small amount of baking soda to fresh milk. (a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline? (b) Why does this milk take a long time to set as curd? 8. Give two important uses of washing soda and baking soda. 9. What is acid rain? What is its pH? How does it affect the aquatic life? 10. What happens when an acid or a base is added to the water? Why does the

beaker appear warm? Why should we always add acid or base to the water and not water to the acid or base.

Column (A) Column (B)

(a) Lactic acid (b) Acetic acid (c) Citric acid (d) Oxalic acid

(i) Tomato (ii) Lemon (iii) Vinegar (iv) Curd



11. On passing excess CO2 through lime water, it first turns milky and then becomes colourless. Explain why ? Write chemical equations.

12. How are bases different from alkalis? Are all bases alkalis? 13. While constructing a house, a builder selects marble flooring and marble top

for kitchen where vinegar and juices of lemon, tamarind etc. are more often used for cooking. Will you agree to this selection and why?

14. Indicate with the help of a diagram the variation of pH with change in concentration of H+ (aq) and OH− (aq) ions.

15. Write the name and formulae of three hydrated salts 16. What happens when calcium carbonate is made to react with hydrochloric

acid?Give the equation of reaction. 17. Why metallic oxides are called basic oxides and non-metallic oxides are

calledacidic oxides ? 18. What is pH scale? What is pH value of salt formed by a (a) Weak acid and strong base? (b) Strong acid and strong base? 19. Explain why sour substances are effective in cleaning copper vessels? 20. A white powder is added while baking breads and cakes to make them soft

and fluffy. What is the name of the powder? What are its main ingredients? 5 Marks: 1. What is water of crystallization? Write the common name and chemical

formula of a commercially important compound which has ten water molecules. How is this compound obtained? Write chemical equations also. List any two uses of this compound

2. An element P does not react with dil. H2SO4. If forms an oxide PO which turns red litmus into blue. Will you call P as a metal or a non-metal? Give reason

3. For making cake, baking powder is taken. If at home your mother uses baking soda instead of baking powder in cake,

(a) how will it affect the taste of the cake and why? (b) how can baking soda be converted into baking powder? (c) what is the role of tartaric acid added to baking soda? 4. A metal carbonate X on reacting with an acid gives a gas which when passed

through a solution Y gives the carbonate back. Onthe other hand, a gas G that is obtained at anode during electrolysis of brine is passed on dry Y, it gives a compound Z, used for disinfecting drinking water. Identity X, Y, G and Z.

5. A dry pellet of a common base B, when kept in open absorbs moisture and turns sticky. The compound is also a by–product of chloralkali process. Identify B. What type of reaction occurs when B is treated with an acidic oxide? Write a balanced chemical equation for one such solution



6. A sulphate salt of Group 2 element of the Periodic Table is a white,soft substance, which can be moulded into different shapes by making its dough. When this compound is left in open for some time, it becomes a solid mass and cannot be used for moulding purposes. Identify the sulphate salt and why does it show such a behaviour? Give the reaction involved.

7. (a) Write down five products formed with the help of common salt on industrial level.

(b) Write down the chemical name of these compounds and one use of each of them.

8. Fill in the blanks a) Acid + ______ Salt + Water. b) _____ + Metal Salt + _____ c) Metal carbonate / metal hydrogen carbonate + acid _______ + _______ + _______.

d) NaOH 2H O _______ + _______ e) Na2CO3 + 10H2O _______.

3. Metals and Non-metals 1Mark: 1. What are amphoteric oxides? Give two examples of amphoteric oxides 2. Name two metals which will displace hydrogen from dilute acids, and two

metals which will not. 3. What type of oxides is formed when non-metals combine with oxygen 4. Name a metal which is the best conductor of electricity and one which is poor

conductor of electricity. 5. Why food cans are coated with tin and not with zinc? 6. Name any two alloys whose electrical conductivity is less than that of pure metals. 7. Name the non-metal with lustre. 8. Define amphoteric oxide. 9. An aqueous solution of Al2O3 is electrolysed. Name the element collected at

anode. 10. An oxide of an element was dissolved in water. The final solution turned red

litmus blue. Is the element metal, non-metal or a metalloid? 11. What happens when cinnabar is heated? 12. Ionic compounds have high melting point. Why? 13. Name two metals which are found in nature in free state. 14. Why Magnesium and calcium float when they react with water? 15. Write the chemical equations of heating of Cu and Fe. 16. Write two chemical equations to show that Al2O3 is an amphoteric oxide.



17. What is galvanization? Why it is done? 18. Hydrogen gas is not evolved generally when metals react with nitric acid.

Explain. 19. Explain the thermit process. Write the chemical equation involved. 20. Distinguish between roasting and calcination. 21. Every ore is a mineral but not every mineral is an ore. Explain. 22. Why highly reactive metals can't be obtained from their oxides using cokeasa

reducing agent? 23. Name one lustrous non-metal. 24. Name two metals that are soft and can be cut with a knife. 25. Number of electrons gained or lost by an element is called its…………….. 26. What are minerals? 27. What is the process of depositing zinc on iron called? 28. Which metal do not react with water at all? 29. Name the ion made by non-metals – cation/anion. 30. Bronze is an alloy made by the combination of……………..and…………….. . 31. Name two metals that are stored in kerosene oil. 32. Arrange copper, silver and aluminium in increasing order of reactivity. 33. Why do we apply oil on iron tools kept in storage? 34. Why calcium is found in the form of compound? 35. Why is pure gold not suitable for making ornaments? 36. What are ionic compounds? 37. Name two metals which do not react with oxygen 38. Name two metals which catch fire if kept in open air 39. Why are metals highly electropositive in nature? 40. Why is sulphide ore converted to its oxide before reduction? 41. What are metalloids? 42. What is an amalgam? 43. Green layer is gradually formed on a copper plate left exposed to air for a week

in a bathroom. What could this green substance be? 44. Which chemical process is used to extract a metal from its oxide? 45. How is corrosion of iron prevented by coating it with a layer of oil? 46. Metal is found to be present in vitamin B-12. Name the metal 47. Why does zinc liberate hydrogen gas when it reacts with dilute hydrochloric acid but copper does not? 48. Which one of the metal in the following group are Au, Na, Cu, Ca? (a) most reactive (b) least reactive 49. How does the term “Ore” differ from “Mineral”? Give an example 50. Show formation of NaCl by transfer of electrons



2Marks: 1. Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the

formation of bubbles in reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how he can identify the produced gas. Write chemical equations for both the reactions.

2. During extraction of metals, electrolytic refining is used to obtain pure metals. (a) Which material will be used as anode and cathodefor refining of silver

metal by this process? (b) Suggest a suitable electrolyte also. 3. Why should the metal sulphides and carbonates be converted to metal

oxides in the process of extraction of metal from them? 4. Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why? 5. Compound X and aluminium are used to join railway tracks. (a)Identify the compound X (b) Name the reaction (c) Write down its reaction. 6. When a metal X is treated with cold water, it gives a basic salt Ywith

molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also writethe reaction involved.

7. A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity.Identify X, Y and Z.

8. What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires?

9. A metal A, which is used in thermite process, when heated with Oxygen gives an oxide B, which is amphoteric in nature. Identify Aand B.

Write down the reactions of oxide B with HCl and NaOH. 10. Give the formulae of the stable binary compounds that would beformed by the

combination of following pairs of elements. (a) Mg and N2 (b) Li and O2 (c) Al and Cl2 (d) K and O2 11. What happens when (a) ZnCO3 is heated in the absence of oxygen? (b) A mixture of Cu2O and Cu2S is heated? 12. Give reasons: (a) Why is pure gold not suitable for making ornaments? (b) Why calcium is found in the form of compound?



13. Give reasons: (a) Why electrical wires are coated with PVC? (b) Why sodium is stored in kerosene oil? 14. To obtain metal from their metal oxide, which chemical process is used? Give

the chemical equation as well. 15. Why magnesium ribbon starts floating in hot water? 16. A non-metal A is an important constituent of our food and forms two oxides B

and C. Oxide B is toxic whereas C causes global warming (a) Identify A, B and C (b) To which Group of Periodic Table does A belong? 17. Give two examples each of the metals that are good conductors and poor

conductors of heat respectively. 18. Name one metal and one non-metal that exist in liquid state at room

temperature. Also name two metals having melting point less than 310 K (37°C) 19. An element A reacts with water to form a compound B which is used in white

washing. The compound B on heating forms an oxide C which on treatment with water gives back B. Identify A, B and C and give the reactions involved.

20. An alkali metal A gives a compound B (molecular mass = 40) onreacting with water. The compound B gives a soluble compound C on treatment with aluminium oxide. Identify A, B and C and give the reaction involved.

21. Give the reaction involved during extraction of zinc from its ore by (a) Roasting of zinc ore (b) Calcinations of zinc ore 22. A metal M does not liberate hydrogen from acids but reacts withoxygen to give

a black colour product. Identify M and black coloured product and also explain the reaction of M with oxygen.

23. An element forms an oxide A2O3 which is acidic in nature. Identify ‘A’ as a metal or non-metal

24. A solution of CuSO4 was kept in an iron pot. After few days the ironpot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved.

25. Explain the following (a) Reactivity of Al decreases if it is dipped in HNO3 (b) Carbon cannot reduce the oxides of Na or Mg 26. Of the three metals X, Y and Z. X reacts with cold water,Y with hotwater and Z

with steam only. Identify X, Y and Z and also arrangethem in order of increasing reactivity.

27. Two ores A and B were taken. On heating ore A gives CO2 whereas, ore B gives SO2. What steps will you take to convert them into metals?

28. Explain the following



(a) NaCl is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as well as in molten state

(b) Metals like Na, K, Ca and Mg are never found in their free state in nature. 29. A student was given Mn, Zn, Fe and Cu metals. Identify which of them (a) Will not displace H2 from dil. HCl. (b) Will react only with steam to give H2 (g). Write the chemical reactions involved. 30. An element A reacts with water to form a compound B which is used in white

washing. The compound B on heating forms an oxide which on treatment with water gives back B. Identify A, B and C and give the reactions involved.

3Marks: 1. The following reaction takes place when aluminium powder is heated with

MnO23 MnO2 (s) + 4 Al (s) →3 Mn (l) + 2 Al2O3 (l) + Heat (a) Is aluminium getting reduced? (b) Is MnO2 getting oxidised? 2. What are the constituents of solder alloy? Which property of solder makes it

suitable for welding electrical wires? 3. Name one metal and one non-metal that exist in liquid state at room

temperature. Also name two metals having melting point less than 310 K (37°C)

4. An alkali metal A gives a compound B (molecular mass = 40) on reacting with water. The compound B gives a soluble compound C on treatment with aluminium oxide. Identify A, B and C and give the reaction involved.

5. A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black colour product. Identify M and black coloured product and also explain the reaction of M with oxygen.

6. You are given a hammer, a battery, a bulb, wires and a switch. (a)How could you use them to distinguish between samples of metals and non-

metals? (b)Assess the usefulness of these tests in distinguishing between metals and

non – metals. 7. You must have seen tarnished copper vessels being cleaned with lemon or

tamarind juice. Explain why these sour substances are effective in cleaning the vessels

8. Differentiate between metal and non-metal on the basis of their chemical properties

9. A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but



after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

10. Diagrammatically show the formation of MgO. 11. Ionic compounds are good conductors of electricity under specific conditions.

Name the two conditions and give reasons. 12. Why Caesium and gallium melt in our palm? 13. Why magnesium ribbon starts floating in hot water? 14. What are ionic compounds? 15. To obtain metal from their metal oxide, which chemical process is used Give

the chemical equation as well. 16. What are the three major steps involved in extraction of a metal after its ore is

mined? 17. Carbonates and sulphide ores are usually converted into oxide ores, why? 18. How does roasting differ from calcinations? Give equations. 19. A zinc rod was kept in a glass container having CuSO4 solution. On

examining, it was found that the blue color of the solution had faded. After few days when the zinc rod was taken out of the solution, a number of small holes were noticed in it. State the reason and give equation of chemical reaction involve

20. Explain the formation of an ionic compound between a metal and a non- metal by transfer of electrons with Mg as the metal and chlorine as the non –metal to illustrate your answer. Give the reaction that occurs.

5 Marks: 1. A non-metal A which is the largest constituent of air, when heated with H2 in

1:3 ratio in the presence of catalyst (Fe) gives a gas B.On heating with O2 it gives an oxide C. If this oxide is passed intowater in the presence of air it gives an acid D which acts as a strong oxidising agent.

(a) Identify A, B, C and D (b) To which group of periodic table does this non-metal belong? 2. Give the steps involved in the extraction of metals of low and medium

reactivity from their respective sulphide ores. 3. Explain the following (a) Reactivity of Al decreases if it is dipped in HNO3 (b) Carbon cannot reduce the oxides of Na or Mg (c) NaCl is not a conductor of electricity in solid state whereas it does conduct

electricity in aqueous solution as well as in molten state (d) Iron articles are galvanised. (e) Metals like Na, K, Ca and Mg are never found in their free state in nature.



4. (i) Given below are the steps for extraction of copper from its ore. Write the reaction involved. (a) Roasting of copper (1) sulphide (b) Reduction of copper (1) oxide with copper (1) sulphide. (c) Electrolytic refining (ii) Draw a neat and well labelled diagram for electrolytic refining of copper 5. Of the three metals X, Y and Z. X reacts with cold water, Y with hot water and

Z with steam only. Identify X, Y and Z and also arrange them in order of increasing reactivity.

6. An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give a product C. An aqueous solution of product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also write down the equations for the reactions involved.

7. Two ores A and B were taken. On heating ore A gives CO2 whereas, ore B gives SO2. What steps will you take to convert them into metals?

8. i) What is reactivity series of metals? Arrange the metals zinc, magnesium, aluminium, copper and iron in a decreasing order of reactivity.

ii) What is observed when you put a) some zinc pieces into blue copper sulphate solution. b) Some copper pieces into green ferrous sulphate solution. iii) Name a metal which combines with hydrogen gas. Name the compound

formed. 9. Give reasons: i) Platinum, gold and silver are used to make jewellery. ii) Sodium and potassium are stored under oil. iii) Aluminium is a highly reactivemetal, still it is used to make utensils for

cooking. iv) Carbonate and sulphide ores are usually converted into oxides during the

process of extraction 10. What is the difference between a mineral and an ore? 11. Differentiate between roasting and calcinations process in metallurgy. 12. What is an alloy? Name the alloy which has iron, nickel and chromium as its

constituent. What is the chief use of this alloy? 13. Explain any two ways to prevent rusting of iron. 14. Explain briefly electrolytic refining method.

Very Short Answer Type Questions: 1. Mention the functional group which always occurs at the terminal position of the carbon chain

of a organic compound. 2. Identify the functional group in the following compounds : (i) CH3COCH3 (ii) HCOOH 3. Name the simplest ketone.



4. Give the name of CH3CH2CH2OH 5. Give the formula and name of an alkane which contains four carbon atoms in each molecule. 6. Make the two possible carbon skeletons with five carbon atoms. 7. Draw the structure of propanone. 8. Draw the structural formula of methanoic acid.

Short Answer Type Questions: 1. (i) Distinguish between saturated hydrocarbon and unsaturated hydrocarbon with the help of

combustion process. (ii) Write the chemical names of C4H10 and C2H2 and draw their structures. 2. State any three physical properties and three uses of ethanol. 3. Carbon can neither form C4+cations nor C4-anions but form covalent compounds. Justify this

statement. Also, give reasons why covalent compounds are poor conductor of electricity. 4. Hydrogen is passed through vegetable oil in presence of the catalyst nickel. (i) Name the process and write the chemical equation. (ii) Write one difference between the physical properties of reactant and product in this

reaction. 5. Distinguish between esterification and saponification reactions with suitable examples along

with chemical equations. 6. An element is a main constituent of paper, diamond and clothes etc. It forms covalent bonds

with itself and other elements. (i) Identify the element. Write its atomic number. (ii) How will be the electron distribution in its various shells? (iii) How it will attain noble gas configuration? 7. List the three characteristics of elements which have periodic change in a period. 8. Chlorine reacts with alkanes through a very fast reaction in the presence of sunlight. What is

this reaction called ? Illustrate it by taking an example of methane reacting with chlorine. 9. Why is ethanoic acid named as glacial acetic acid ? Why are mineral acids considered strong

acids while carboxylic acids are weak ? Compare the expected pH value and the change in colour of pH paper in hydrochloric acid and ethanoic acid using universal indicator.

10. (i) Write your observation, if you dip a red litmus paper in soap solution. (ii) Explain the formation of scum in hard water. (iii) Suggest one method to remove the temporary hardness of water. 11. Li, Be, B, C, N, O, F and Ne are present in the second period. (i) Give reason why they are placed in the same period? (ii) What is the maximum number of electrons that can be accommodated in L shell? (iii) What would be the valency of nitrogen with atomic number 7? 12. Give the balanced equation of the reaction in which alcohol is converted to carboxylic acid.

Why is it called oxidation reaction ? What is the role of oxidizing agents in it ? 13. One of the commercially important carbon compounds is ethanol. Mention its two uses. When

a small piece of sodium is dropped in ethanol a gas is evolved. How can we test the gas evolved ?

14. (a) While washing clothes in washing machine the clothes are agitated in soap solution for some time. Why is this agitation necessary to clean the clothes ?



(b) Why the detergents remain effective in hard water for washing clothes whereas with soap foam is formed with difficulty ?

15. Where do we find non – metals in the periodic table? Do non – metals lose or gain electrons to attain nearest inert gas configuration? What is the nature of their oxides?

16. Substitution reactions and Addition reactions are the characteristic properties of saturated and unsaturated hydrocarbons respectively. Distinguish between substitution reaction and addition reaction by taking an example of methane and ethene respectively.

17. (i) Draw the electron dot structure of : (a) H2S (b) F2 (ii) Which type of bond is found in F2? 18. An element A is in the third group of periodic table. Write the chemical formula of its oxide

and chloride.

19. Test tubes A and B initially have brown color solution known as bromine water. On passing

methane in test tube A, there is no change whereas on passing ethene in test tube B decolorization of bromine water takes place.

(i) Write the reaction between ethene and bromine water. (ii) State the type of reaction. (iii) Account for the decolorization of bromine water in test tube B. 20. Dehydration of ethanol gives rise to an unsaturated hydrocarbon. Give the balanced chemical

equation of the reaction. Name the dehydrating agent and also mention the temperature at which the reaction takes place.

21. (i) Each soap molecule has two parts. Identify these two parts from the figure given above. (ii) What is „micelle ? (iii) Why are detergents harmful for environment ? 22. The electronic configuration of four elements A, B, C and D is as given under A -2, 1 B -2, 2 C- 2, 8, 2 D – 2 (a) Which amongst them belong to the same group? Write the group number. (b) Which amongst them belong to the same period? Write the period number. (c) Which element amongst them is inert? Name it. 23. Give the balanced equation of the reaction in which alcohol is converted to carboxylic acid.

Why is it called oxidation reaction ? What is the role of oxidizing agents in it ? 24. Write balanced chemical equation of the reaction of ethanoic acid with : (i) Sodium carbonate (ii) Sodium hydrogen carbonate (iii) Sodium hydroxide 25. Write the molecular, electronic and structural formulae of ethyne.



26. Complete the following table : Element

Group Period

Li Cl Ar

27. What is catalytic hydrogenation? How is it carried out? Give the balanced chemical equation of reaction involved.

28. A gas is evolved when sodium carbonate reacts with propanoic acid. Write the balanced chemical equation between these two given reactants. Show the acidic nature of propanoic acid by any two methods.

29. Atom of an element contains five electrons in its valence shell. This element is major component of air. It exists as a diatomic molecule.

(i) Identify the element. (ii) Show the bond formed between two atoms of this element. (iii) Write the nature of the bond between the two atoms. 30. The atomic number of X is 13. (i) Identify its position in terms of group and period in the modern periodic table. (ii) Compare its atomic size with the first member of the period. (iii) State whether its oxide is acidic or basic in nature? 31. Explain the following reactions with chemical equations. (i) Oxidation (ii) Hydrogenation (iii) Substitution 32. A colorless organic liquid „X has no action on any litmus paper and is used as a nail polish

remover. Another colorless organic liquid „Y of molecular formula C2H6O is used in tincture of iodine.

(i) Identify the functional group present in „X and to which homologous series does „Y belong ?

(ii) Write the name and chemical formula of C2H6O. 33. Draw the electron dot structure of O2, NH3 and CCl4. 34. The electronic configuration of four elements A, B, C, and D, is given as follows : A – 2, 8 B - 2, 8, 1 C - 2, 8, 2 D - 2, 8, 8 (a) Which of them belong to the same period? Name the period. (b) Which of them belong to the same group? Name the group. (c) Which amongst them would form (i) Monovalent cation (ii) Divalent cation

LONG Answer Type Questions: 1. The two members of group 14 in the periodic table are carbon (atomic no.6) and silicon (atomic

no.14). (a) Write electronic configuration of both elements. (b) Deduce their valencies. (c) Name the element which is more electronegative answer with proper reason. (d) Find out whether these elements are metal or non-metal ? Give reason for your answer.



2. An element X(atomic no. 11) reacts with an element Y (atomic no. 17) to form a monovalent halide.

(a) Identify the position of X and Y in group and period in the periodic table. (b) State whether these elements are metal or non-metal ? (c) Describe nature of oxide of element X. (d) Draw electron dot structure of the halide. 3. The formulae of oxides of two elements X and Y are XO and Y2O3 respectively. (a) Find the valencies of X and Y. (b) Identify the groups in which they would be placed in the modern periodic table. (c) Name one more element belonging to each of these groups. 4. Give reasons why : (a) Atomic size increases down the group for elements in the periodic table (b) Atomic size decreases on moving from left to right in a period in the periodic table. (c) Metallic character increases for elements down the group in the periodic table (d) Metallic character decreases across the period in the periodic table. (e) Atomic number is more fundamental for elements property for the classification of

elements. 5. The two members of group 14 in the periodic table are carbon (atomic no.6) and silicon (atomic

no.14). (a) Write electronic configuration of both elements. (b) Deduce their valencies. (c) Name the element which is more electronegative answer with proper reason. (d) Find out whether these elements are metal or non-metal ? Give reason for your answer. 6. Give reasons why : (a) Atomic size increases down the group for elements in the periodic table (b) Atomic size decreases on moving from left to right in a period in the periodic table. (c) Metallic character increases for elements down the group in the periodic table (d) Metallic character decreases across the period in the periodic table. (e) Atomic number is more fundamental for elements property for the classification of

elements. 7. The two members of group 14 in the periodic table are carbon (atomic no.6) and silicon (atomic

no.14). (a) Write electronic configuration of both elements. (b) Deduce their valencies. (c) Name the element which is more electronegative answer with proper reason. (d) Find out whether these elements are metal or non-metal ? Give reason for your answer. 8. Define atomic size of an element. Atomic radii of some elements like C, Li, N, O, B and Be are 77, 152, 74, 66, 88 and 111 pm

respectively. 9. Rearrange them in decreasing order of their atomic radii. Name the elements which have largest and the smallest size respectively. Give reason for the change in atomic radius as you move from left to right in a period.



Short Answer Type Questions: 1. Name the acids and bases from which the following salts may be obtained:Potassium

sulphate and calcium chloride. 2. The reaction of metal ‘X’ with Fe2O3 is highly exothermic and is used to join railway

tracks. Identify the metal ‘X’. Write the chemical equation of the reaction. 3. Two solutions A and B have pH values of 3.0 and 10.5 respectively. Which of these

will turn (i)Blue litmus solution to red and (ii)Phenolphthalein from colourless to pink ? Justify your answer in each case Name one metal each which is extracted by : (a)reduction with carbon (b)electrolytic reduction (c)reduction with aluminium (d)reduction with heat alone 4. Write the chemical name of baking soda. Write balanced chemical equation for its

preparation. Mention its one use. 5. Name the reducing agent in the following reaction : 3MnO2+4 Al 3 Mn+2 Al2O3

State which is more reactive, Mnor Al and why ? 6. The enamel of the teeth is made of a compound 'X'. It is the hardest substance of the

body. It does not dissolve in water but gets corroded when the pH of mouth is lowered below 5.5

(i)Identify the compound 'X' (ii)How does it undergo damage due to eating sweets ? What should we do to prevent

tooth decay ? 7. Match the metals given in column - II with the methods used for their extraction given

in column – I. Column – I Column - II (1) Reduction with

carbon (a)

Al

(2) Electrolytic reduction (b) Zn (3) Reduction with

aluminium (c)

Na

(d) Mn 8. A milk man adds very small amount of baking soda in fresh milk. (a)Why does he shift the pH of fresh milk from 6 to slightly

alkaline ? (b)Why does this milk take a long time to set as curd ? 9. Name the gas which is liberated when an acid reacts with a metal. Illustrate with an

example. How will you test the presence of this gas ? 10. A white powder 'X' is used by the doctors for supporting fractured bones. (a)Write the name and chemical formula of the 'X'.



(b)Write chemical equation for the reaction when this powder 'X' is mixed with water. 11. In one method of rust prevention, the iron is not coated with anything. Name the

method and define it. 12. A compound of sodium 'X' is used in kitchen to make the pakoras crispy. It is also

used to remove acidity in stomach. (i)Identify the compound 'X' and write its chemical formula. (ii)What chemical reaction occurs on heating it during the cooking of food. 13. Classify the following into acidic oxides and basic oxides : Na2O, SO2, MgO, CO2

14. Define an acid and a base. Name one weak acid and one strong base. 15. What is meant by amphoteric oxides? Choose the amphoteric oxides from the

following : Na2O, ZnO, CO2, Al2O3, H2O Short Answer Type Questions: 1. State reason for the following : (i) dry HCl gas does not change the colour of the dry blue litmus paper. (ii) alcohol and glucose also contain hydrogen, but do not conduct electricity. (iii) Concentration of H3O+ ions is affected when a solution of an acid is diluted. 2. P, Q and R are three elements which undergo chemical reactions according to the

following equations : P2O3+2Q Q2O+2P

3RSO4+2Q Q2(SO4)3 +3R

3RO+2P P2O3+3R

Answer the following questions with reasons : (a)Which element is the most reactive? (b)Which element is the least reactive? (c)State the types of reactions listed above. 3. (a)A non-metal X exists in two different forms Y and Z. Y is the hardest natural

substance whereas Z is a good conductor of electricity. Identify X, Y, Z. (b)An element, X, on reaction with oxygen forms an oxide XO2. The oxide when

dissolved in water turns blue litmus red. State whether element X a is metal or a non-metal.

(c)Name the metal which is alloyed with copper to make bronze. 4. Explain the action of dilute hydrochloric acid on the following with chemical equations

: (i)magnesium ribbon (ii)sodium hydroxide (iii)crushed egg shells 5. When soap is scrubbed on a stain of curry on a white cloth, why does it become

reddish brown and turns yellow again when the cloth is washed with plenty of water?



6. Below are two reactions : (i)2KI+Cl2 → 2KCl+I2 (ii)2K+Cl2 → 2KCl

7. Describe how sodium and chlorine form sodium chloride? Name the type of bonding shown in the structure.(Atomic number : Na 11, Cl 17)

8. List two examples of each of the following : (i)Salts which do not contain metal ions. (ii)Salts which are obtained from weak acid and weak base. (iii)Salts which are obtained from strong acid and strong base 9. List the raw materials used in the manufacture of baking soda. Write two important

uses of this compound.In the reaction MnO2+4HClMnCl2+2H2O+Cl2

(i)Name the substance oxidised.(ii) Name the substance reduced. (iii)Name the oxidising agent and the reducing agent. 10. (a)Write any two properties of ionic compounds. (b)Show the formation of aluminium chloride by the transfer of electrons between the

atoms. (Atomic number of aluminium and chlorine are 13 and 17 respectively.) 11. State reason for the following : (i)dry HCl gas does not change the colour of the dry blue litmus paper. (ii)alcohol and glucose also contain hydrogen, but do not conduct electricity.

(iii)Concentration of H3O+ ions is affected when a solution of an acid is diluted.

12. Answer the following questions : (i)State the colour of phenolphthalein in soap solution. (ii)Name the by - product of chlor - alkali process which is used for the manufacture of

bleaching powder.

(iii)Name one indicator which specifies the various levels of H+ ion concentration. 13. What is meant by the term rancidity. To prevent rancidity of foods containing fats or

oils, some substances are added to them, what are these substances called ? Suggest two preventive measures of slowing down this process.

14. Distinguish between the following : (i)Electrolytic reduction and electrolytic refining (ii)Mineral and ore (iii)Alloys and amalgams 15. (a)What is meant by exothermic and endothermic reactions ? (b)Identify whether the following reactions are exothermic or endothermic : (i)CaO+ 2O → Ca(O )2 (ii)CH4+2O2 → CO2+H2O

16. State in tabular form the name of the acid and the base from which the following salts have been formed. Also mention whether the salt is acidic or basic in nature.

(i)Potassium acetate (ii)Ammonium sulphate



17. State two properties of each of the following metals which make them suitable for : (i)copper and aluminium for making electric wires (ii)gold, platinum and silver are used to make jewellery (iii)copper to make hot water tank 18. (a)Write any two properties of ionic compounds. (b)Show the formation of aluminium chloride by the transfer of electrons between the

atoms. (Atomic number of aluminium and chlorine are 13 and 17 respectively.) 19. (a)What will be the action of litmus on : (i)Dry ammonia gas (ii)Solution of ammonia gas in water (b)State the observations made on adding ammonium hydroxide to aqueous solution

of : (i)Ferrous sulphate (ii)aluminium chloride 20. Write balanced chemical equations for the following reactions : (i)Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (ii)Barium chloride reacts with zinc sulphate to give zinc chloride and barium

sulphate. (iii)Natural gas burns in air to form carbon dioxide and water. 21. Explain the following terms : (a)Ore (b)Mineral (c)Gangue 22. Give reason for the following : (a)Ionic compounds are usually hard. (b)Sodium chloride has a high melting point. (c)Non-metals do not displace hydrogen from dilute acids 23. Write the chemical formula of washing soda. How can it be obtained from baking

soda? Name two industrial uses of washing soda. 24. Write the balanced chemical equations for the following reactions : (i)Calcium hydroxide + Carbon dioxide Calcium carbonate + Water (ii)Aluminium + Copper chloride Aluminium chloride + copper. (iii)Calcium carbonate hydrochloric acid Calcium chloride water carbon

dioxide 25. What is meant by electrolytic reduction ? How is sodium obtained from its molten

chloride ? Explain 26. Name the gas which is usually liberated when an acid reacts with a metal. Illustrate

with an example. How will you test for the presence of this gas? 27. Complete the following table :

Sample solution Red litmus solution

Blue litmus solution

Phenolphthalein solution

Acetic acid Sodium hydroxide



Baking Soda 28. (i)List any two observations. (ii)Name the type of chemical reaction taking place. (iii)Write the chemical equation of the reaction. 29. Answer the following questions : (a)Name two metals which melt when kept on Palm. (b)Name two metals which do not react with oxygen even on heating. What is the

likely position of such metals in the reactivity series ? (c)What happens when steam is passed over hot iron. Write its chemical equation. 30. Describe an activity to find out the conditions under which iron rusts. LONG Answer Type Questions: 1. (a)Balance the following chemical equations : (i)NaOH+H2SO4Na2SO4H2O (ii) PbO+CPb+CO2(iii) Fe2O3+Al

Al2O3+Fe+Heat

(b)Write the balanced chemical equations for the following reactions : (i)Barium chloride+PotassiumsulphateBarium sulphate+Potassium chloride (ii)Zinc+Silver nitrate Zinc nitrate+Silver 2. Comment on the following : (i)An acid reacts with a substance 'X' produces a gas which burns with pop sound.

What is the nature of 'X' ? (ii)An acid when reacts with Z, produces CO2 gas. What can be Z ?

(iii)CaO and SO2 are two oxides. Name the oxide which will react with a base. Give

reason. (iv)A sodium compound is used for removing permanent hardness of water. Name

that compound. (v)A substance on treatment with chlorine gas yields bleaching powder. Name the

substance. 3. Define a chemical reaction. State four observations which help us to determine that a

chemical reaction has taken place. Write one example of each observation with a balanced chemical equation.

4. (a)Illustrate an activity to investigate whether all compounds containing hydrogen are acidic.

(b)What happens when hydrochloric acid and sodium hydroxide are dissolved in water. Explain giving equation of each.

5. Identify the type of chemical reaction in the following statements and define each of them :

(i)Digestion of food in our body (ii)Rusting of iron (iii)Heating of manganese dioxide with aluminium powder



(iv)Blue colour of copper sulphate solution disappears when iron filings are added to it

(v)Dilute hydrochloric acid is added to sodium hydroxide solution to form sodium chloride and water

6. (a)List two natural and two synthetic indicators. (b)What are olfactory indicators ? Mention two examples. (c)Differentiate between strong acid and weak acid. 7. (a)Giving reason identify the substance oxidised and the substance reduced in each of

the following chemical reactions : (i)H2+CuOCu+H2O (ii)H2S+SO23S+2H2O

(b)Name the term used to represent a reaction in which oxidation and reduction take place simultaneously.

8. How baking powder is produced from baking soda ? What happens when baking powder is mixed in water ? Write the chemical equation

involved. Why baking soda is used as an antacid ? 9. Define a chemical reaction. State four observations which help us to determine that a


10. State reason for the following statements : (i)Tap water conducts electricity whereas distilled water does not. (ii)Dry hydrogen chloride gas does not turn blue litmus red whereas dilute

hydrochloric acid does. (iii)During summer season, a milkman usually adds a very small amount of baking

soda to fresh milk. (iv)For dilution of an acid, acid is added into water and not water into acid. (v)Ammonia is a base but does not contain a hydroxyl group. 11. (a)Define corrosion, what name is given to the corrosion of iron ? (b)Name the colour of coating formed on silver and copper articles, when exposed to

air ? (c)List two damages caused by corrosion and suggest how corrosion can be prevented. 12. Write balanced chemical equations for the following statements : (i)Bleaching powder is kept open in air. (ii)Blue crystals of copper sulphate are heated. (iii)Chlorine gas is passed through dry slaked lime. (iv)Carbon dioxide gas is passed through lime water. (v)NaOH solution is heated with zinc granules. 13. (a)Define corrosion, what name is given to the corrosion of iron ? (b)Name the colour of coating formed on silver and copper articles, when exposed to

air ? (c)List two damages caused by corrosion and suggest how corrosion can be prevented.



14. A metal is treated with dilute sulphuric acid. The gas evolved is collected by the method shown in the figure. Answer the following questions :

(i)Name the gas evolved. (ii)Name the type of chemical reaction that takes place. (iii)Name the method of collection of gas. (iv)Is the gas soluble or insoluble in water ? (v)Is the gas lighter or heavier than air ?

15. Define a chemical reaction. State four observations which help us to determine that a


16. Name the material used for the preparation of plaster of Paris. Write chemical equation for the reaction involved. What will happen if heating is not controlled while preparing plaster of Paris. Which property of plaster of Paris is utilised in making casts for broken limbs in hospital. Write an equation to show the reaction between plaster of Paris and water.

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