aieee achiever 2 - solutions

8/2/2019 Aieee Achiever 2 - Solutions

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CHEMISTRY CREST AIEEE ACHIEVER 2

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Maximum Marks: 120

Question paper format and Marking scheme:

1. This question paper has 30 questions of equal weight age. Each question is allotted 4(four) marks for eachcorrect response.

2. (one fourth) of total marks allotted to each question i.e., 1 mark will be deducted for indicating incorrect

response

3. No deduction from the total score will be made if no response is indicated for an item in the answer sheet.

4. There is only one correct response for each question. Filling up more than one response in each questionwill be treated as wrong response and marks for wrong response will be deducted accordingly.


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1. A proton and an -particle are accelerated through the same potential difference. The ratio of the

de-Broglie wavelengths of proton and -particle is

(1) 2 (2)1

2(3) 2 2 (4) 2

Sol. (3)

Proton is 11H Charge = 1, Mass = 1

-particle is 42 He Charge = 2, Mass = 4

h

2e.V.m =

h

2 2 V m

=

p

h

2 2 V 4m =

p

p

h

2 1 V m =

P 16

2

=

P 2 2

=

2. The pair of structures given below represents

(1) Conformational isomers (2) Position isomers

(3) Chain isomers (4) None

Sol. (2)These are positional isomers


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3. A coloured precipitate is obtained when H2S gas is passed through an aqueous solution of salt in

presence of ammonium hydroxide. The precipitate dissolves in dilute HCl & reacts with NaOH to

give white precipitate, which on standing turns in to a brown/black mass. The brown/black mass

on fusion with KNO3 & Na2CO3 gives green mass. The cation of the salt is(1) Co2+ (2) Mg2+

(3) Ni2+

(4) Mn2+

Sol. (4)

( ) ( )

( )

2

2 2 2( )

2 3 2 3 2 2 4 2 2

/

2 2

HCl NaOH

OMn H S MnS MnCl MnO

MnO KNO Na CO H O Na MnO KNO NaOH CO

+ +

+ + + + + +fusion

Buff coloured Brown black coloured

Greenmass

4. A mixture containing 0.05 mole of 2 2 7K Cr O and 0.02 mole of 4KMnO was treated with excess of KI

in acidic medium. The liberated iodine required 1.0 L of 2 2 3Na S O solution for titration.

Concentration of 2 2 3Na S O solution was

(1) 10.40 mol L (2) 10.20 mol L (3) 10.25 mol L (4) 10.30 mol L

Sol. (1)

In acidic medium,Eq. wt. of 2 2 7

6

molar massK Cr O =

In acidic medium, Eq. wt. of4

5

Molar massKMnO =

Eq. of 2 2 3Na S O = Eq. of 2I liberated = eq. of 4KMnO + eq. of 2 2 7K Cr O

1 0.02 5 0.05 6N = +

0.4N = (or) 0.4M =

5. 2/ 4 structural products

Cl hX

. X is

Sol. (4)

Given numbers indicate different types of hydrogens which can be substituted by Cl atoms


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6. Which one of the following oxo-acids of sulphur has S-S linkage and one lone pair of electrons

on each sulphur atom

(1) H2S2O6 (Dithionic acid) (2) H2S2O5 (Di or pyro sulphurous acid)

(3) H2S2O3 (Thiosulphuric acid) (4) H2S2O4 (Dithionous acid or Disulphurous acid)

Sol. (4)

7. An ideal solution of two liquids A and B is placed in a cylinder containing piston. Piston is pulled

out isothermally so that the volume of the liquid decreases but that of vapours increases.

Negligibly small amount of liquid was left and mole fraction of A in vapour is 0.4. If oA

P 0.4atm=

and oBP 1.2atm= at the experimental temperature, which of the following is the total pressure at

which the liquid is almost evaporated?

(1) 0.334atm (2) 0.667atm (3) 1atm (4) 2atm

Sol. (2)0 0

T A A B BP P x P x= +

0

A AA

T

A

T

P xy

P0.4x

0.4P

=

=

A Tx P =

0

B BB

T

B

T

P xy

P1.2x

(1 0.4) P

=

=

TB

Px

2 =

A B B Ax x 1; x 1/ 3; x 2 / 3+ = = =

T

2 1P 0.4 1.2 0.667atm

3 3 = + =


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8. Observe the reactions/ tests given for the following compound and select whether it gives + ve or

- ve tests

Sol. (1)

Reacts with Na metal as the compound given has acidic hydrogens ( -OH, -COOH, C CH )

Reacts with NaHCO3 as the compound given has COOH groupReacts with 2,4 DNP as the compound given has CHO group ( Test given by carbonyl compounds)

Does not react with Lucas reagent as the compound given has phenolic group and not alcoholic group

9. Select the correct statement(s) .

(a) The graphite is diamagnetic and diamond is paramagnetic in nature.

(b) Graphite acts as a metallic conductor along the layers of carbon atoms and as semiconductor

perpendicular to the layers of the carbon atoms.

(c) Graphite is less denser than diamond

(d) C60 is called Buckminster fullerene(1) b,c,d (2) a,b,d (3) a,b,c,d (4) a,b,c

Sol. (1)Both are diamagnetic as all electrons are paired.

10. Ammonium hydrogen sulphide dissociates according to the equation

( ) ( ) ( )4 3 2NH HS S NH g H S g+ If the observed pressure of the mixture is 1.12 atmosphere at 1060C, what is the equilibrium

constant Kp of the reaction ?

(1) 0.3136 atm2

(2) 2 atm2

(3) 1 atm2

(4) 0.4842 atm2

Sol. (1)

( ) ( ) ( )4 3 2

0 0 0

s gg

eq

NH HS NH H S

t

t t xatm xatm

+

=

=

2 1.12T

P x= =

0.56x = 2 20.3136

PK x atm= =


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11. Which of the following carbonyl gives 4-methyl pent -3-en-2-one on reaction with dilute NaOH

solution with heating.

(1)Acetaldehyde (2)Acetone (3) Formaldehyde (4) Propanal

Sol. (2)4-Methyl pent -3-en-2-one is Aldol condensation product of acetone.

12. About alkali metal liquid NH3 solution which of following statement is not true ?

(1) Blue colour is due to ammoniated electrons.(2) Blue colour changes to bronze on dilution due to formation of metal clusters.

(3) with increse in concentration of alkali metals paramagnetic nature decreases due to electron-electroncombination.

(4)On heating blue colour becomes colourless due to formation of metal amide and H2 gas.

Sol. (2)

Blue colour changes to bronze with increase in concentration of alkali metal due to formation of metal

clusters.

13. A solution of 200 ml of 1M KOH is added to 200 ml of 1M HCl and the mixture is shaken well. The

rise in temperature T1 is noted. The experiment is repeated by using 100 ml each solution and

increase in temperature T2 is again noted. Which of the following is correct ?

(1)1 2

T T= (2)2 1

2T T= (3)1 2

2T T= (4)1 2

4T T=

Sol. (1)

Case I : 200 ml 1M KOH + 200 ml 1M HCl

Case II: 100 ml 1M KOH + 100 ml 1 M HClEquivalent to

2H O produced due to neutralisation in case II is half that of case I.

Due to this energy release, 12

2

HH =

Case I H1= m1ST1(1)

Case II H2= m2ST2 (or) 1 1 22 2

H mST= (2)

From (1) and (2),T1 =T2.


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14. Arrange the following diazonium ions in decreasing order of their rate of coupling with phenol

Sol. (3)

Electron withdrawing group increases electrophilicity and hence rate of coupling reaction(electrophilic substitution)

15. Match List-Iwith List-II

List-I(Metals) List-II(Process/methods involved in extraction process)

(a) Au 1. Self reduction

(b) Al 2. Liquation

(c) Pb 3. Electrolysis

(d) Sn 4. Bayer's process(a) (b) (c) (d)

(1) 3 1 2 4

(2) 3 4 1 2(3) 1 2 4 3

(4) 3 2 4 1

Sol. (2)

Electrolysis is used in the refining of gold

In Bayer's process, pure aluminium oxide is obtained from the bauxite ore.

Pb is extracted by self reduction methodA low melting metal like tin can be refined by liquation method. .

16. A certain acid-base indicator is present in 75% blue form at pH 5. This indicator has acid form

red and basic form blue. At what pH will the indicator show 90% red form? [log 3 = 0.4771](1) 5.47 (2) 3.56

(3) 3.39 (4) 10.01

Sol. (2)

HIn H In

Acidform Basic form

(Red) (Blue)

+ +


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[ ]In

5

H InK

HIn

H x1010 75

25 90

+

+

=

= =

5

5

H 3

75 90H 10

25 10

27 10

P 5 log3

5 3log3

5 1.4313

3.5687

+

=

=

=

=

=

=

17. A metallic carbide on treatment with water gives a colourless gas which burns readily in air and

gives a precipitate with ammonical silver nitrate solution. The gas evolved is(1) CH4 (2) C2H6 (3) C2H4 (4) C2H2

Sol. (4)

( )4 32 2 22 ( )

NH OH AgNOCaC H O Ca OH HC CH Ag C C Ag

+ + ++ + White ppt

18. Which of the following will displace the halogen from the solution of the halide ?

(1) Br2 added to NaI (2) Br2 added to NaCl

(3) Cl2 added to KCl (4) Cl2 added to NaF

Sol. (1)

Smaller halogen (i.e., stronger oxidising agent) displaces bigger halogen (i.e. weaker oxidising agent)

from solution of its halide

19. Which of the following is correct?(1) Specific conductivity of a solution decreases with dilution, whereas molar conductivity increases

with dilution

(2) Specific conductivity of a solution increases with dilution, whereas molar conductivity decreaseswith dilution

(3) Both specific conductivity and molar conductivity decreases with dilution

(4) Both specific conductivity and molar conductivity increases with dilution

Sol. (1)With dilution, no. of ions per unit volume decreases


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20. The compound A in the following reaction is

Sol. (4)Wurtz reaction, generally used for the preparation of symmetrical alkanes

21. The true statement about oxoacids of phosphorus is(1) Order of their reducing strength is H3PO2 > H3PO3 > H3PO4.

(2) Hybridisation of phosphorus is sp3

in all these.

(3) All have one P=O bond(4) All of these.

Sol. (4)Greater the no of P H bonds , greater is the reducing power

22.

An element crystallizes in bcc as well as fcc lattices having edge lengths 300 and 400 pm

respectively. The ratio of their densities would be

(1) 1.18 (2) 2.28 (3) 3.38 (4) 4.48

Sol. (1)

( )

( )

310

Abcc

30

fcc3

10

A

2 M

300 10 Nd

4 M 10d

400x10 N

=

=( )

( )

3

3

4 641.185

27 23 2= =


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23. The product (P) of the following reaction is

Sol. (2)

Electrophilic aromatic substitution ( I+ Cl- )- CH3 group is o, p director.

24. All the following complex ions are found to be paramagnetic :

P : [FeF6]3-

; Q : [CoF6]3-

R : [V(H2O)6]3+

; S : [Ti(H2O)6]3+

The correct order of their paramagnetic moment (spin only) is :

(1) P > Q > R > S (2) P < Q < R < S (3) P = Q = R = S (4) P > R > Q > S

Sol. (1)

On the basis of number of unpaired electrons the correct order is P > Q > R > S

[FeF6]3- Fe3+

weak field

n = 5

[CoF6]3- Co3+weak field

n = 4

[V(H2O)6]3+ V3+


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n = 2

[Ti(H2O)6]3+

n = 1

25. In a reaction Aproducts, the rate is doubled when the concentration of A is increased 4 times. If

50% of the reaction occurs in 1414 sec , how long would it takes for the completion of 75%

reaction.

(1) 4242sec (2) 2825 sec (3) 2414 sec (4) 2121 sec

Sol. (3)

Order =1/2

First 1t 1414sec2

=

n 1

a1therefore second t 14142 a

2

1 14141t 1000sec2 a 2

=

= =

total time for 75% reaction is 1414+1000=2414 sec

26. Which of the following sets of bases are present in both DNA and RNA(1) Adenine, uracil, thymine (2)Adenine, guanine, cytosine

(3) Adenine, guanine, uracil (4) Adenine, guanine, thymine

Sol. (2)Adenine, guanine, cytosine are the bases commonly present in both DNA and RNA.

Difference lies in thymine and uracil

DNA contains thymine whereas RNA contains uracil

27. Which of the following is a wrong order with respect to the property mentioned againsteach(1) (NO) > (NO) > (NO)

+[bond length](2) H2 > H2

+> He2

+[bond energy]

(3) O22-

> O2 > O2++

[Paramagnetic moment](4) NO2

+> NO2 > NO2 [bond angle]

Sol. (3)

(NO) > (NO) > (NO)+

Bond order 2 2.5 3Bond order is inversely proportional to bondlength


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H2 > H2+

> He2+

Bond order 1 0.5 0.5( more anti bonding)

Bond order is directly proportional to bond energy. Anti bonding e- leads to destabilisation

O22-

> O2++

> O2

No of unpaired e - 0 0 2

Greater the no of unpaired e -, greater is the paramagnetic moment

So, wrong

NO2+

> NO2 > NO2

Bond angle 1800

1330

1150

28. One litre of a gas at 300 atm and 473 K is compressed to a pressure of 600 atmosphere and 273K.

The compressibility factors found from the curves are 1.072 and 1.375 respectively at the initial

and final states. Calculate the final volume

(1) 370.15 cc (2) 480 cc

(3) 500 cc (4) 200 cc

Sol. (1)P1V1 = Z1nRT1

P2V2 = Z2nRT2

2 2 1 2

2 1 1 1

.PV T Z

T PV Z

=

2 2 1 12

1 1 2

.Z T PV

VZ T P

=

=1.375 273 300 1000

1.072 473 600

= 370.15 cc

29. Which set is correctly matched.(1) Dacron or Terylene : Condensation polymer

(2) PVC : Biodegradable polymer(3) Nylon-6, 6 : Addition polymer

(4) Buna-S rubber : Natural polymer

Sol. (1)Dacron or Nylon is a condensation polymer of terephthalic acid and ethylene glycol


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30. The borax bead is chemically

(1) B2O3 (2) Na2B4O7 (3) Na3BO3 (4) B2O3 + NaBO2

Sol. (4)Borax on heating, first loses water molecules and swells up. On further heating, it turns into a

transparent liquid, which solidifies into glass like material known as borax bead.

The metaborates of many transition metals have characteristic colours and, therefore, borax bead testcan be used to identify them in the laboratory.

aieee achiever 2 - solutions

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