Study material CLASS XTH

SUBJECT - SCIENCE

Weightage in CBSE examination: 25 marks .

PREPARED BY BHOOLAN SAROJ

PGT CHEMISTRY - JNV AURANGABAD.

CHAPTER 1- CHEMICAL REACTIONS AND EQUATIONS

1. During chemical reactions, chemical composition of substances changes or new substances are formed.

2.Chemical reactions can be written in chemical equation form which should be always balanced.

3. Types of Chemical Reactions

S NO Types of reactions Examples

1 Combination reaction

A single product is formed from two or more reactants.

2Mg +O2→2MgO

2 Decomposition reaction

A single reactant breaks down to yield two or more products.

i) Thermal decomposition2Pb(NO3)2 → 2PbO + 4NO2 +O2

ii) Electrolysis 2H2O →2H2 +O2

iii) Photo chemical reaction 2AgBr →2Ag +Br2

3 Displacement reaction

One element is displaced by another Zn + CuSO4→ ZnSO4 + Cu

element.

4 Double displacement reaction

Exchange of ions between reactants. AgNO3 +NaCl →AgCl +NaNO3

5 Redox reaction

Both oxidation and reduction take place simultaneously

CuO + H2 → Cu + H2O

4. i)Exothermic reaction:A chemical reaction in which heat energy is evolved.C + O2 →CO2 (g) + heat

ii)Endothermic reaction:A chemical reaction in which heat energy is absorbed.

ZnCO3 + Heat →ZnO + CO2

5 .Redox reaction:Chemical reaction in which both oxidation and reduction take place simultaneously.Oxidation:Reaction that involves the gain of oxygen or loss of hydrogen.

Reduction:Reaction that shows the loss of oxygen or gain of hydrogenZnO + C →Zn + COZnO is reduced to Zn -reduction C is oxidized to CO ------oxidation6. Effects of oxidation reactions in our daily life:

a)Corrosion: It is an undesirable change that occurs in metals, when they are attacked by moisture, air, acids and bases.

Corrosion (rusting) of iron: Fe2O3. xH2O (Hydrated iron oxide)Corrosion of copper:CuCO3.Cu (OH) 2 (Basic copper carbonate)

Corrosion of silver:Ag2S (Silver sulphide) Corrosion of Aluminum: Al2O3 (Aluminum oxide)

b)Rancidity: Undesirable change that takes place in oil containing food items due to the oxidation of fatty acids.Preventive methods (1)Adding antioxidants to the food materials. (2) Storing food in air tight container (3) Flushing out air with nitrogen gas. (4) Refrigeration

CHAPTER 2--ACIDS, BASES AND SALTS

Acids: Substances which turn blue litmus solution red are called acids. Acids are sour in taste

Bases: Substances which change red litmus solution blue are called bases. They are bitter in taste.

Mineral Acids: Acids which are obtained from minerals like sulphates, nitrates, chlorides etc. are called mineral acids, e.g., H2SO4(Sulphuric acid), HNO3(Nitric acid) and HCl(Hydrochloric acid).

Organic Acids: Acids which are obtained from plants and animals are called organic acids.e.g. citric acid, ascorbic acid, tartaric acid, lactic acid, acetic acid .

Hydronium Ions: They are formed by reaction of H+ (from acid) and H2O. It is because H+ is unstable.

Universal Indicator: A universal indicator is a mixture of indicators which shows a gradual but well-marked series of colour changes over a very wide range of change in concentration of H+

ion.

Strong Acids: Acids which dissociate into ions completely are called strong acids. Eg. H2SO4, HCl

Weak Acids: Acids which do not dissociate into ions completely are called weak acids Eg.. citric acid, acetic acid.

Chemical properties of acids(i) Acids react with active metals to give salt and hydrogen gas.

(ii) Acids react with metal carbonate and metals hydrogen carbonate to give salt, water and carbon dioxide.

(iii) Acids react with bases to give salt and water. This reaction is called neutralization reaction.

(iv) Acids react with metals oxides to give salt and water.

Chemical properties of Bases (i) Reaction with Metals – Certain metals such as Zinc, Aluminiumand Tin react

with alkali solutions on heating and hydrogen gas is evolved (ii) Reaction with acids – Bases react with acids to form salt and water.Indicators - Indicators are substances which indicate the acidic or basic nature of the solution by their colour change.

pH scale : A scale for measuring hydrogen ion concentration in a solution. The pH of a solution is defined as the negative logarithm of hydrogen ion concentration in moles per litre.pH =-log [H+]pH =-log [H3O+]where [H+] or [H3O+] represents concentrations of hydrogen ions in solution.

The pH of a neutral solution is 7 The pH of a acidic solution is < 7 The pH of a basic solution is > 7

Some Important Compounds and their uses

Common Name Chemical name Chemical formula

Uses

Washing soda Sodium carbonate decahydrate

Na2CO3.10H2O Manufacture of borax, caustic soda, softening of hard water

Baking soda Sodium hydrogen carbonate

NaHCO3 Used as antacid, ingredient of baking powder

Bleaching powder

Calcium oxychloride CaOCl2 Bleaching clothes, used as oxidizing agent, disinfecting water, manufacture of chloroform

Plaster of Paris Calcium sulphate hemihydrate

CaSO4 .1/2H2O Plastering fractured bones, making toys ,decorative materials ,statues

EQUATIONS OF ACIDS,BASES AND SALTSAcid + Metal Salt + Hydrogen gasH2SO4+Zn ZnSO4+H2

Base+ Metal Salt + Hydrogen gas2NaOH + Zn Na2ZnO2 + H2

(Sodium zincate)Base + Acid Salt + WaterNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)Acids give hydronium ions in waterHCl+H2O H3O++ Cl-

Bases generate OH- ions in waterNaOH(aq) + H2O Na+(aq)+OH-(aq)

Reactions Of Important chemical compoundsPreparation of Bleaching powderBy the action of chlorine on dry slaked limeCa(OH)2+Cl2-----CaOCl2+H2O On heating, baking soda liberates CO2

2NaHCO3 Heat Na2CO3 + H2O + CO2

Washing soda(Sodium carbonatedecahydrate)Na2CO3 + 10H2O Na2CO3.10H2OPlaster of ParisPreparation of plaster of ParisCaSO42H2O 373K(Heat) CaSO4.1/2 H2O +1.1/2H2O On mixing plaster of Paris with water,gypsum is obtainedCaSO4.1/2H2O +1 ½ H2O CaSO4 .2H2O

CHAPTER 3 : METALS AND NON-METALS

MIND MAP

EXTRACTION OF METALS

CHAPTER-4CARBON AND ITS COMPOUNDS

IMPORTANT POINTS

The chemical symbol of Carbon is C. Its atomic number is 6 and mass number is 12.It is a non-metallic element.

ALLOTROPES OF CARBON

ISOMERISM - The phenomenon in which a compound has the same molecular formula but different structures is called isomerism.

ISOMERS -The compounds which have the same molecular formula but different structuresand different properties are called isomers.IUPAC – International Union of Pure and Applied Chemistry.

FUNCTIONAL GROUPS: Atoms or group of atoms responsible for the chemical properties of an organic compound.

HOMOLOGOUS SERIES –A series of compounds having same functional group and similar chemical properties but differ by--CH2 unit between two successive members.

CHAPTER 5

PERIODIC CLASSIFICATION OF ELEMENTS

Dobereiner’s TriadsDobereiner observed that when elements were arranged into groups of three in the order of their increasing atomic masses, the atomic mass of the middle element was the arithmetic mean of rest of the two.Limitation Could be applied only to limited number of elements.

Newlands’ Law of OctavesNewlands found that every eighth element has chemical properties when they are arranged in increasing order of their atomic masses.Limitations

Could be valid up to calcium only Newlands assumed that only56 elements existed in nature and no more elements would

be discovered.

Mendeleev's Periodic Classification

Mendeleev’s Periodic Law states that the properties of elements are the periodic function of their atomic masses.Merits of Mendeleev’s Periodic Table

Mendeleev left some blank spaces for undiscoveredelements. Mendeleev predicted the discovery of some elements and named them as eka-boron, eka-

aluminium and eka-silicon. Noble gases discovered later could be placed without disturbing the existing order.

Limitations of Mendeleev’s Periodic Table Position of Hydrogen- Could not assign a correct position to hydrogen as hydrogen

resembles alkali metals as well as halogens Position of Isotopes- Isotopes are placed in same position though they have different

atomic masses Separation of chemically similar elements while dissimilar elements are placed in

the same group.Modern Periodic Classification

Modern Periodic Law states that properties of elements are the periodic function of their atomic numbers.

Groups in Modern Periodic Table:Group 1 Alkali metals

Group 2 Alkaline earth metals

Groups 3 to 12 Transition elements

Group 13 Boron family

Group 14 Carbon family

Group 15 Nitrogen family

Group 16 Oxygen family

Group 17 Halogens

Group 18 Noble gases

Periods in Modern Periodic Table

Period No of elements1st period 2 (H,He)2nd and 3rd period 8 (Li,Be,B ,C,N,O,F,Ne)4th and 5th period 186th period 327th period  Incomplete period

Trends in Modern Periodic Table:

Property Variation along the group Variation along the period

Valency Remains the same Increasesup to group 14 then decreases

Atomic radii Increases Decreases

Metallic character Increases Decreases

Electropositive character Increases Decreases

Electronegativity Decreases Increases

DIAGRAMS

PRACTICE PROBLEMS

I MARK QUESTIONS

.Q. 1. Give an example of an endothermic reaction.

Q. 2. Name a metal which is both ductile as well as malleable.

Q3 Identify the substance that is getting oxidised in the reaction:

CuO (s) + H2 (g) → Cu (s) + H2 O (l)

Q4. Give an example of a displacement reaction.

Q.5. Give the names of the functional groups (i) — CHO | (ii) — COOH

Q.Give an example of a metal which is the best conductor of heat.

Q6. It is advised to pour acid into water rather than water to acid for the dilution of acids. Why ?

Q. 7. Name the product other than water formed on burning or Etnanol in air.

Q. 8. Why does magnesium powder react much more rapidly than magnesium ribbon with dilute Acids.

2 MARKS QUESTIONS

Q. 9. Write two observations you would make when quick lime is added to water.

Q. 10. Choose a metal out of the following which reacts with hot water but not with cold water: Sodium, Magnesium, Iron Mention the products formed during the reaction.

Q. 11. a. What is meant by pH of a solution?

b. State one difference between a strong electrolyte and a weak electrolyte. Give one example of each.

Q. 12. What is an alloy? Name the constituents of 22- carat gold. Why is 24-carat gold converted to 22-carat gold ?

Q. 13. a. Name the functional group present in propanone (acetone).

b. What is the product formed when propane is reduced? Name the reducing agent used.

c. What happens when propanone is oxidised by alkaline KMnO4?

Q. 14. Given below are the pH values of four different liquids: 7.0, 14.0, 4.0, 2.0

Which of these could be that of

i. lemon juice,ii. ii. distilled water,iii. iii. 1 M sodium hydroxide solution, iv. iv. tomato juice?

3 MARKS QUESTIONS

Q. 15. i. Name the raw materials used in the manufacture of sodium carbonate by Solvay process.

ii. How is the sodium hydrogen carbonate formed during Solvay process separated from a mixture of NH4CL and NaHCO3?

iii. How is sodium carbonate obtained from sodium hydrogen carbonate?

Q. 16. What is the action of litmus on:

i. Dry ammonia gas

ii. Solution of ammonia gas in water.

b. State the observations you would make on adding ammonium hydroxide to aqueous solutions of:

i. Ferrous sulphate

ii. Aluminium chloride.

Or

Explain the following terms by giving one example of each:

i. Mineralii. ii. Ore iii. iii. Gangue

Q. 17. i. How is methanal obtained from methanol?

ii. Write the chemical equation of the reaction involved in the preparation of methanal from methanol. iii. Mention one use of an aqueous solution of methanal in the biology laboratory.

Q 18 Write the chemical equation for the reaction of hot aluminium with steam.

Q.19 What justifies sulphuric acid being called the "king of chemicals' ? Why does sugar turn black in contact with concentrated sulphuric acid ?

Q.20How is plaster of Paris chemically different from gypsum ? How may they be interconverted ? Write one use of plaster of Paris.

Q.21. (a) Write the chemical equation representing the reaction for the preparation of methanal from methanol.

(b) What happens when methanal is mixed with :

(i) Ammoniacal silver nitrate solution and the mixture is warmed.

(ii) Fehling's reagent and the mixture is warmed.

(c) Complete the reaction equation : HCHO + HCN →

Q22. Write the formulae for the given compounds and name the functional groups present in each of them : (i) Ethanoic acid

(ii) Propanone

(iii) Nitromethane

Q.23. (a) State the relation between hydrogen ion concentration of an aqueous solution and its pH.

(b) The pH of an aqueous solution decreases from 3 to 2. Calculate how many times the hydrogen ion concentration of the solution will change

Q 24 How is plaster of Paris chemically different from gypsum ? How may they be interconverted ? Write one use of plaster of Paris. 2

Q25.Allotropy is a property shown by which class of substances, elements, compounds or mixtures ? Give one example of allotropy.

Q26. Explain the following regarding the manufacture of ammonia by Haber's process, the reaction being :

N2 (g) + 3H2 (g)…………….> 2NH3 (g) + heat

(i) This reaction is carried out at a high temperature even though it is an exothermic reaction.

(ii) (ii) To make ammonia, the mixture of N2 and H2 gases is passed over heated iron.

Q. 27 . a. Name the organic acid present in vinegar. Write its chemical formula also.

b. Name the products formed when i. Ethanol burns in air. ii. Sodium ethanoate is heated with soda lime.

Q.28. (a) Give Arrhenius definition of an acid and a base.

(b) Choose strong acid and strong base from the following : CH3 COOH, NH4 OH, KOH, HCl

Q.29 . When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y, Z.

Q30 Write the balanced equation for the following reaction and identify the type of reaction in each case. I) Barium Iodide + Potassium bromide ………………………….>Barium bromide.+ Potassium iodide

ii) Hydrogen + Chloride (g) Hydrogen chloride (g)

Q.31 . (a) Balance the chemical equation : Fe(s) + H2o(g) …………………..> Fe3o4 + H2

(b) Identify the type of reaction in the equation given below.

Na2 SO4 + BaCl2(aq) ………> BaSO4(aq)+ NaCl(aq)

Q.32. Write the name and molecular formula of an organic compound having its name suffixed with ‘- ol’ and having two carbon atoms in the molecule. With the help of a balanced chemical equation indicate what happens when it is heated with excess of conc. H2 SO4 .

Q.33. An ester has the molecular formula C4 H8 O2 . Write its structural formula. What happens when this ester is heated in the presence of sodium hydroxide solution ? Write the balanced chemical equation for the reaction and name the products. What is a saponification reaction ?

Q34. State two characteristic features of carbon which when put together give rise to a large number of carbon compounds.

Q35. The atom of an element has an electronic configuration 2, 8, 7.

(i) What is the atomic number of this element and in which period of the Modern Periodic Table will it be located ?

(ii) Will this element be a metal or non-metal ? Why ?

(iii) How will it form an ion ? What will be the nature of charge on it ?

Q.36What is a homologous series? Write the name and draw the structure of the second member of the alkene series

Q37.Give one example each of a) Metal having valency 2.

b) Non metal having valency 2. c) Element with completely filled outermost shell. d) Element with three shells, having 4 electrons in the outermost shell.

Q38. How do the following traits change in a period from left to right in the periodic table –

a) Atomic size b) Valency c) Metallic character.Q What are isomers? Draw all possible isomers of C4 H10 and name them.

Q39 Two elements ‗X‘ and ‗Y‘ belong to the second group of the periodic table. ‗X‘ has 2 shells and ‗Y‘ has 3 shells in it –

a) Which of these is more metallic in nature and why? b) What is the formula of the chloride of ‗X‘ and sulphide of ‗Y‘? c) Is the valency of ‗X‘ same as that of ‗Y‘ or different? Why?

LONG ANSWER TYPE QUESTIONS( 5 MARKS )

Q.40. a) Write equations for the reaction of ethanol (C2 H5 OH) with –

i) Sodium metal ii) conc. H2 SO4

iii) Ethanoic acid in the presence of conc. H2 SO4

b) Why does micelle formation take place when soap is added to water? Why is soap ineffective for washing in hard water?

Q. 41. a. Name an important ore of iron. Write its formula.

b. How is this ore concentrated?

c. Describe with chemical equations, the reactions taking place in the furnace to obtain iron from the concentrated ore.

Or

Give reasons for the following;

a. Metals conduct electricity.

b. Metals generally do not form compounds with hydrogen.

c. A piece of zinc placed in blue copper sulphate solution decolourises it.

d. Alumina is dissolved in molten cryolite for electrolysis to obtain aluminium metal.

e. Nitrogen gas is used, to preserve food.

Q.42. (a) State two properties of carbon which lead to carbon forming more compounds than any other element. (b) Name the product formed when ethanoic acid reacts with pure ethanol in the presence of an acid catalyst. Write the chemical equation for the reaction involved. (c) How would you distinguish experimentally between an alcohol and a carboxylic acid

OR

(a) (i) What is a homologous series ? (ii) Why do we see a gradation in physical properties of members of a homologous series as the molecular mass of members increases ?(iii) Why do chemical properties of members of a homologous series remain more or less the same ?

(b) How are soaps chemically different from detergents ? How is it that detergents are more effective than soaps in hard water.

Q43. Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but different number of electrons in their outermost shell. It was found that elements A and G combine to form an ionic compound. This compound is added in’ a small amount to almost all vegetable dishes during cooking. Oxides of elements A and B are basic in nature while those of E and F are acidic. The oxide of D is almost neutral. Based on the above information answer the following questions:

(i) To which group or period of the periodic table do the listed elements belong ?

(ii) What would be the nature of compound formed by a combination of elements B and F ?

(i) Which two of these elements could definitely be metals ?(ii) (iv) Which one of the eight elements is most likely to be found in gaseous state at

room temperature ?

(v) If the number of electrons in the outermost shell of elements C and G be 3 and 7 respectively, write the formula of the compound formed by the combination of C and G

Q. 44. What is an alloy? How is an alloy made? List two purposes of making alloys. Mention the constituents and two properties of each of the following alloys:

i. Stainless steel

ii. Brass

Q45. Write the names and symbols of two most reactive metals belonging to group I of the periodic table. Explain by drawing electronic structure how either one of the two metals reacts with a halogen. With which name is the bond formed between these elements known and what is the class of the compound so formed known ? State any four physical properties of such compounds.

Or

What is meant by refining of a metals ? Name the most widely used method of refining impure metals produced by various reduction processes. Describe with the help of a labelled diagram how this method may be used for refining of copper. (5)

Q.46. (a) Write chemical equations for the reactions involved in obtaining pure alumina from the mineral bauxite which has impurities of iron oxide and silica.

(b) Draw a labelled diagram of the electrolytic tank cell used for the extraction of aluminium from alumina. 5

OR

(a) What is corrosion of metals ? Name one metal which does not corrode and one which corrodes on being kept in atmosphere.

(b) How will you show that the rusting of iron needs oxygen and moisture at the same time.

Q47 . (a) Give two methods to prevent the rusting of iron ?

(b) Name the ores of the following metals (i) mercury and (ii) zinc

(c) Explain, with the help of a diagram, how impure copper metal can be refined ? Label the important arrangements in the experimental set up.

Or

(a) How the metals at the top of the reactivity series can be extracted from their ores ? Explain with an example. (b) Name any one alloy made from (i) a metal and a non metal and (ii) two metals.

Application based questions

Chapter-1 CHEMICAL REACTION AND EQUATIONS Q-1. Why parents are advised to discourage their children to eat chips and junk food?

Chapter-2 ACID, BASES AND SALTS Q-2. Brushing our teeth twice a day is a well known saying. Justify this statement. Q-3. Farmers are using a large number. of Pesticides and fertilizers in their fields to increase crop production and to enhance their profits. But by doing so they are causing damage to the soil as well as to the environment. Do you agree with this

statement? Why should we avoid eating fruits and vegetables without washing them properly?

Chapter -3 METALS AND NONMETALS Q-4. Gold is a very precious metal. Pure gold is very soft it is therefore not suitable for making jewellery. It is alloyed with either Silver or Copper to make it hard. But sometimes jewellers mix a large quantity of copper and Silver in gold to earn more profit. Q-i. What precautions should you take while purchasing gold jewellery? Q-(ii). Why does Government insist on purchasing Hall Marked jewellery? Q-5. Corrosion is a serious problem. Every year an enormous amount of money is spend to replace damaged iron. What steps can be taken to prevent this damage. Q-6. Mercury is the only metal found in the liquid state. It is largely used in thermometers to measure the temperature. But mercury is a very dangerous metal as its density is very high. What two precautions you would take while handling the equipments containing Mercury?

Chaper-4. CARBON AND ITS COMPOUNDSQ-7. Mrs. Anita observed that her cooking utensils are becoming black in colour and the flame of her gas stove is yellowish in colour what can be the reason for this sooty flame. How is this problem harmful for our environment? What steps should be taken to stop this process.Q-8. Ethanol is used on a large scale at commercial level this is a very useful chemical. It is commonly called alcohol and is the active ingredient of alcoholic drink. But consumption of alcohol also causes drunkenness and this practice is Socially condemned. As a responsible student of class –X what steps you would take to discourage the use of alcohol.Q-9. You must have seen advertisements stating that some vegetable oils are healthy. Saturated fatty acids which are said to be harmful for health. Why vegetable oils are considered healthy then Saturated fatty acids (ghee)? What precautions you would take in selecting a cooking oil.Chapter – 5 PERIODIC CLASSIFICATION OF ELEMENTSQ-10. Ria and Rama are students of Class-X. Ria is very much organized and maintained. The teachers love her. She earns a great respect in the class where as Rama is un-organised and always faces a lot of problems in handling life situations. (i). In your opinion how organization help in daily life? (ii). How can you relate the above fact with the chapter classification of elements. How classification of elements help us in studying them properly?

Q-11. Adulteration is becoming a very serious problem of our society. Study reveals that more people die because of food adulteration rather than hunger. Shopkeepers mix harmful chemicals and things in food items to earn more profit which may even lead to deaths. (i). Being a responsible citizen how can you fight against adulteration? (ii). Give an example of food adulteration. (iii) How will you test about the adulteration in this food item.

HIGH OREDER THINKING SKILL QUESTIONS Chapter 1 Chemical reactions and equations

Q.1 What are the two methods which can prevent the rancidity of fatty foods? Q.2 Write two examples of everyday life , where redox reactions are taking place. Q.3 solid calcium oxide was taken in a container and water was added slowly to it : i) write the observation ii) Write the chemical formula of the product formed.b) What happens when carbon dioxide gas is bubbled through lime water:a) In small amount ? (b) In excess/iii) Why do we apply paint on iron articles. Chapter-2 ACID, BASES AND SALTSQ.1 Although acetic acid is highly soluble in water but still it is a weak acid . Explain why?Q.2 What happens when nitric acid is added to egg shell?2Q.3 a) mention the pH range within which our body works.Explain how antacids give relief from acidity.Write the name of one such antacid. b) Fresh milk has the pH of 6. How does the pH will change as it turns to curd? Explain your answer.C) A milkman adds a very small amount of baking soda to fresh milk . Why does this milk take a longer time to set as a curd?d) Mention the nature of toothpastes .how do they Prevent toothdey?Chapter -3 METALS AND NONMETALS Q.1 Why magnesium ribbon starts floating when it is placed in hot water?Q.2 What will happen when :a) magnesium is treated with very dilute nitric acid?b) steam is passed over red hot iron?Q.3 Of the three metals X, Y nad Z .X reacts with cold water, Y with hot water and Z with steam only. Identify X,Y and Z and also arranfe them in order of increasing reactivity..

Q.4 Distinguish between the following: i) Electrolytic reduction and electrolytic refiningii) Mineral and oreiii) alloys and amalgams.

Chaper-4. CARBON AND ITS COMPOUNDSQ.1 An organic compound burns with a sooty flame. Is it a saturated or an unsaturated compound?Q.2 Carbon, group 14 element in the periodic table ,is known to form compounds with many elements. Write an example of compound formed with :a) Chlorine ( Group 17 of periodic table)b) Oxygen ( Group 16)Q.3 A compound C ) Molecular formula C2H4O2) reacts with Na metal to form a compound R and evolves a gas which burns with a pop sound . Compound C on treatment with an alcohol A in presence of an acid forms a sweet smelling compound S ( C3H6O2).On addition of NaOH to C, it also gives R and water. S on treatment with NaOH solution gives back R and A. Identify C,R,A,S and write down the reactions involved.Chapter – 5 PERIODIC CLASSIFICATION OF ELEMENTSQ.1 Arrange the following elements in the increasing order of their metallic character:Mg, Ca, K,Ge, GaQ.2compare the radii of two species X and Y .Give reasons for your answer.a) X has 12 protons and 12 electrons .b) Y has 12 protons and 10 electrons.

VALUE BASED QUESTIONS

Q.1 Asmita visited her grandmother during summer holidays.Her grandmother prepared chips for her and stored it in airtight containers.

a) What value is shown by her grandmother?b) Why did Asmita’s grandmother store the snack in airtight container?

Ans: a) Scientific temperament / concern for healthc) Toprevent the food items from rancidity.

Q. 2Anita bought silver jewellery along with her friend Rita. Anita advised Rita to make sure that the jewellery was kept in a sealed box and not exposed to air; but Rita forgot and left it open. After some months when Rita decided to wear it, she found the jewellery all black. Rita was very upset.

a. Why did the jewellery become black when exposed to air?b. What is this process called?c. What were the values shown by Anita?

Q.3 Meera and her mother were travelling in a CNG auto. The auto driver took the auto to the CNG filling station for filling the empty cylinder. Meera asked her mother about the gas used to fill the cylinder. Her mother replied that the gas used was CNG.CNG is used in place of petrol or diesel because it is cheaper, pollution free and eco-friendly.Answer the following questionsa) What is the long form of CNG?b) Name the main constituent of CNG.c) What value have you leant after reading the text?

Practical based question (2 marks)

Experiment 1Finding the pH of the following samples by using pH paper/ universal indicator(a) Dilute Hydrochloric Acid(b) Dilute NaOH solution(c) Dilute Ethanoic Acid Solutiond) Lemon juice(e) Water(f) Dilute Hydrogen Carbonate solutionStudying the properties of acids and bases (HCI & NaOH) by their reaction with(a) Litmus solution (Blue/Red)(b) Zinc metal(c) Solid sodium carbonateQ.1Solid sodium bicarbonate was placed on a strip of pH paper. What was the change in colour

Q.2 A student adds a few drops of the universal indicator to a solution of dilute hydrochloric acid .What will be the colour change he observe.

Q.3 A student dips pH papers in solutions of A and B and observes that the pH paper turns blue and orange respectively in them . What does he infer.

Q.4 When a student added zinc granules to dilute HCI, a colourless and odourless gas was evolved,which was then tested with a burning match stick; what would be observed?Q.5 . When a few drops of phenolphthalein are added to a dilute solution of sodium hydroxide, a pink colour is produced . what will be the colour of the final mixture when excess of HCl is added to it ?

Experiment 2

Performing and observing the following reactions and classifying themblue when(a) Combination reaction(b) Decomposition reaction(c) Displacement reaction(d) Double displacement reaction(i) Action of water on quick lime(ii) Action of heat on ferrous sulphate crystals

(iii) Iron nails kept in copper sulphate solution(iv) Reaction between sodium sulphate and barium chloride solution.

Q.1 What happens when ferrous sulphate crystals are heated?Q.2. When an iron rod is dipped into a solution of copper sulphate, copper is displaced. Why is it so?Q.3 . When we add water to quick lime we observe some changes. On the basis of those changes what conclusion can be concluded about the reaction between quick lime and water? Q.4 Rahul adds aqueous solution of barium chloride is added to an aqueous solution of sodium sulphate. What would he observe?

Experiment 3

(a) Observing the action of zinc ,iron,copper and aluminium metals on the following salt solutions:(i) ZnSo,(aq)(i) CuSo,(ag(i) FeSo,(aq)(iv)Al2 (SO4)3

b) Arranging Zn, Fe, Cu and Al in the decreasing order of reactivity based on the above result.Q.1Iron filings were added to a solution of copper sulphate. After 10 minutes, it

was observed that the blue colour of the solution changes and a layer gets deposited on iron filings. What is the colour of the solution and the layer deposited?Q.2 . A strip of copper was placed in a beaker containing zine sulphate solution. On observing the strip next day, was thereany colour change in the dtrip.Q.3 On adding zinc granules to freshly prepared ferrous sulphate solution, what is observed?

Experiment8study of the following properties of acetic acid (ethanoic acid):(i) odour(ii) solubility in water(ii) effect on litmus

(v) reaction with sodium Hydrogen Carbonate

Q1 What happens when 2 mL of acetic acid was added in drops to 5 mL of water? Q.2 Ram adds acetic acid solution to solid sodium hydrogencarbonate. What would he

Observe. Q.3 Devansh was asked to identify the test tube containing acetic acid out of the four test tubes A, B,C and D filled with different liquids. He smelled each of them and found.(i) A gave very sweet smell.(ii) Bgave lightly pungent smell.

(iii) C was odourless(iv) D gave a bad odour.

Which test tube contains acetic acid?

Q.4 1.1ml glacialacetic acid and 1ml of ethanol are mixed together in a test tube. Few drops of concentrated sulphuricacid is added in themixturearewarmed in a waterbath for5 min.

a.Name theresultant compound formed.b.Represent the above changebya chemical equation .c.What term is given to such areactiond.Whatarethe special characteristics of the compound formed. 2. An organic compound with molecular formula C2H4O2 produces brisk effervescence on addition of sodium carbonate /bicarbonate.a .Identify the organic compound.

b. Name the gas evolved.

PREPARED BY BHOOLAN SAROJ PGT CHEMISTRY JNV AURANGABAD MAHARASHTRA