AL/2020/12/E

KOg;gjpg;GupikAilaJ / All Rights Reserved

1

Part−I

1. Which of the following has the highest 1st electron gain energy?

1.N 2. Ne 3. O 4.Li 5. B

2. At different temperatures the standard Gibbs free energies of a reaction is stated below

X(g) + Y(g)⟶ 2Z(g)

T/K ΔGo/kJmol-1

500 −100.5

1000 −150

Find the standard enthalpy of the reaction (ΔHo)?

1. −50kJmol-1 2. −51kJmol-1 3. 10.2kJmol-1 4. 50kJmol-1 5. 51kJmol-1

3. The correct increasing order of basicity of the given molecules?

Introduction: This paper contains 6 pages, 10 MCQ, 1 structured essay and essay. Answer all the

questions.

Write your index number in the space provided,

In part I question from 1 to 10 select the most appropriate answers from (1),(2),(3),(4),(5)

Universal gas constant R = 8.314 J K-1mol-1

Avogadro constant Na = 6.022×1023 mol-1

Plank’s constant h= 6.626×10-34 Js

Velocity of light c = 3×108 ms-1

K→

NH2 NH−C−CH3

║

O

L→ M → CH3CH2NH2 N→ CH3CH2NH−CH3 O → NH3

AL/2020/12/E

KOg;gjpg;GupikAilaJ / All Rights Reserved

2

1. K<L<M<O<N

2. L<K<M<O<N

3. K<L<O<M<N

4. L<K<O<M<N

5. L<K<O<N<M

4. Consider the following equilibrium reaction𝑋(𝑔) + 𝑌(𝑔) ⇌ 2𝑀(𝑔). In a closed container of volume

1dm3 a mole of X(g) and b mole of 𝑌(𝑔) are taken and allowed to react. At T K c mole of M(g) is

produced at equilibrium. Select the correct expression for Kc at temperature T?

1 Kc= c2 /(a-c) 2. Kc= c2 /(a-c)(b-c) 3. Kc= c2 /(a-c/2)(b-c/2)

4. Kc= c2 /(a-c)2 5. Kc= c2 /(a-c/2)

5. The correct statement/s from the following?

A- methanoic acid can be oxidized by tollen’s reagent.

Gives N2 evolution with

Reacts slower when compared to

1.Bonly 2. Aonly 3. B,C only 4. Conly 5. A,B,C all

6. Which of the following is true regarding the S block elements ; (Li-Cs, Be-Ba)?

1. all elements are capable to react with water and release H2(g)

2. Li has the ability to form Li2O,Li2O2 when reacted with air

3. all group I elements can react with N2

4. all group II elements can react with N2

5. all group I hydrides are covalent

7. Which of the following is/are true regarding the kinetics of rection?

(a) the value of rate of reaction and rate constant of a particular reaction increases by the same

amount when the temperature is increased

OH

B→

N2+Cl-

CHO

CH3

CHO

C→ When added to Fehling

solution

AL/2020/12/E

KOg;gjpg;GupikAilaJ / All Rights Reserved

3

(b) in a reaction in which catalyst is used the rate of reaction changes with the concentration of

catalyst.

(c) rate order can change the unit of rate constant but not the unit of rate of reaction

(d)in a balanced chemical equation if the stoichiometric coefficient of one reactant is greater/lesser

than order of it then the reaction is multistep.

8. Which of the following is/are true regarding the rate order?

(a) rate order of an elementary reaction is a whole number

(b) in an elementary reaction the order and molecularity are same.

(c) not always order and molecularity are same.

(d) the overall order of the reaction is the sum of powers of the concentration of reactants in the

rate expression

9. Stat1 : the boiling point of CBr4 is less than CHCl3.

Stat2 : CHCl3 is polar and CBr4 is non polar.

10. Stat1 : in an imaginary reaction 2𝐴(𝑎𝑞) + 𝐵(𝑎𝑞) ⇌ 𝐶(𝑎𝑞) + 𝐻2𝑂(𝑙) change in the concentration of

H2O(l) does not change equilibrium forward or backward

Stat2: in the expression of equilibrium constant [H2O(l)] does not apper

*****

AL/2020/12/E

KOg;gjpg;GupikAilaJ / All Rights Reserved

4

Part II (Structured essay)

The relative molar mass of hydrocarbon A is 58.

1. Give the molecular formula of A.(C=12 ,H=1)

2. Give the suitable structures for A.

3. To a non-cyclic hydrocarbon B of 1 mole 2 mole of H2 is added and allowed for catalytic

hydrogenation and forms 1 mole of A. give the structure of A?

4. give the possible structures of B

1) 2)

3) 4)

5. B gives red precipitate with ammonical Cu2Cl2give the suitable structure for B

6. C, the isomer of B reacts with H2SO4 and HgSO4 and form D. D reacts with acidified

2,4 - DNPH and gives orange precipitate E. give the structures of C,D,E

C D E

b) i) Give the structures of X, Y, Z in the following series of reaction

𝐶𝐻3 − 𝐶 ≡ 𝐶 − 𝐻 dil H2SO4 X water NaOH Y P2O5/∆ Z NaBH4 P HgSO4

Reaction i reaction ii reaction iii

AL/2020/12/E

KOg;gjpg;GupikAilaJ / All Rights Reserved

5

X Y

Z P

ii) Identify the reaction type for the reactions i,ii,iii

Nucleophilic addition, nucleophilic substitution, electrophilic addition, electrophilic substitution

reaction i :

reaction ii :

reaction iii :

c) i)complete the above table.

Major product Nucleophile/electrophile

1) CH3−CH2−CH2I water; 𝐍𝐚𝐎𝐇→

2)

Dil H2SO4

3) CH3COCl

dry AlCl3

4) 𝑪𝑯𝟑

𝑪𝑯𝟑 − 𝑪𝑯𝟐 − 𝑪𝑯 − 𝑪𝒍 C2H5OH

KOH

*****

𝑪𝑯𝟑

𝑪𝑯𝟑 −𝑪 = 𝑪𝑯𝟐

AL/2020/12/E

KOg;gjpg;GupikAilaJ / All Rights Reserved

6

Part-II(Essay)

(a)

i. Derive Avogadro’s law from ideal gas equation.

ii. By the decomposition of 𝐾𝐶𝑙𝑂3 𝑂2 can be obtained. The gas obtained by heating certain

amount of 𝐾𝐶𝑙𝑂3(𝑠) is collected by the downward displacement of water at 270𝐶

temperature and 1.03 × 105𝑃𝑎 pressure. The volume collected was 150𝑐𝑚3 at 270𝐶 the

saturated vapour pressure of water is 0.03 × 105𝑃𝑎. find the molar volume of 𝑂2 ?

(b)

i. 𝐴(𝑔) + 2𝐵(𝑔) ⇌ 2𝐶(𝑔)

In a container 1.0 𝑚𝑜𝑙 𝐴(𝑔) and 2.0𝑚𝑜𝑙 𝐵(𝑔) are added and the temperature is increased for

600𝐾 for the occurrence of reaction. At equilibrium 0.4𝑚𝑜𝑙 𝐶(𝑔) is formed. At this

condition the total pressure of container is 2.8 × 105𝑃𝑎 . Find the 𝑘𝑝 of this reaction at

600𝐾.

ii. When the above equilibrium mixture is cooled to 300𝐾 certain part of 𝐴(𝑔), 𝐵(𝑔) are

liquefied. This liquid solution becomes an ideal solution which is in equilibrium with its

vapour phase. Also 𝐶(𝑔) does not dissolve in liquid phase and the no.of moles of C in gas

phase is 0.20𝑚𝑜𝑙. now the pressure of vapour phase is 9 × 104𝑃𝑎 and the molfraction of

𝐴(𝑔), 𝐵(𝑔) in vapour phase is 3: 5

A. Find the partial pressures of 𝐶(𝑔),𝐵(𝑔), 𝐴(𝑔) at 300𝐾

B. Find the saturated vapour pressures of 𝐶(𝑔),𝐵(𝑔), 𝐴(𝑔) at 300𝐾

C. Give the assumptions you made in these calculations.

(c) To a solution containing 0.1𝑚𝑜𝑙𝑑𝑚−3 𝑁𝑎𝐶𝑙 and 0.01𝑚𝑜𝑙𝑑𝑚−3 𝐾2𝐶𝑟𝑂4 of volume 25 𝑚𝑙

0.1𝑚𝑜𝑙𝑑𝑚−3 𝐴𝑔𝑁𝑂3 is added drop wisely.

[𝐾𝑠𝑝(𝐴𝑔𝐶𝑙) = 1.6 × 10−10𝑚𝑜𝑙2𝑙−2, 𝐾𝑠𝑝(𝐴𝑔2𝐶𝑟𝑂4) = 9 × 10

−12𝑚𝑜𝑙3𝑙−3]

i. Which will be the 1st precipitate?

ii. At the instance at which the second precipitate is formed find the concentration of the

anion of the 1st precipitate.

*****