#### 11th Standard Chemistry Physical and Chemical Equilibrium English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

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Chemistry

Time : 00:20:00 Hrs
Total Marks : 20

20 x 1 = 20
1. ${K_c\over K_p}$ for the reaction,
N2(g) + 3H2(g) ⇌ 2NH3(g) is

(a)

${1\over RT}$

(b)

$\sqrt{RT}$

(c)

RT

(d)

(RT)2

2. In which of the following equilibrium, KP and KC are not equal?

(a)

2 NO(g) ⇌ N2(g) + O2(g)

(b)

SO2 (g) + NO2 ⇌ SO3(g) + NO(g)

(c)

H2(g) + I2(g) ⇌ 2HI(g)

(d)

PCl5 (g) ⇌ PCl3(g) + Cl2(g)

3. The values of KP1 and KP2 for the reactions
X ⇌ Y + Z
A ⇌ 2B are in the ratio 9: 1 if degree of dissociation and initial concentration of X and A be equal then total pressure at equilibrium P1 and P2 are in the ratio

(a)

36: 1

(b)

1: 1

(c)

3: 1

(d)

1: 9

4. In a chemical equilibrium, the rate constant for the forward reaction is 2.5 × 102 and the equilibrium constant is 50. The rate constant for the reverse reaction is,

(a)

11.5

(b)

5

(c)

2 x 102

(d)

2 x 10-3

5. The equilibrium constants of the following reactions are:

 N2 + 3H2 ⇌ 2NH3   : K1 N2 + O2 ⇌ 2NO      : K2 H2 + ½O2 ⇌ H2O   : K3

The equilibrium constant (K) for the reaction ;
${ 2NH }_{ 3 }+5/2{ O }_{ 2 }\overset { K }{ \rightleftharpoons } 2NO+{ 3H }_{ 2 }{ O },$ will be

(a)

$K_2^3{K_3\over K_1}$

(b)

$K_1{K_3^3\over K_2}$

(c)

$K_2{K_3^3\over K_1}$

(d)

$K_2{K_3\over K_1}$

6. Hydrogen (a moles) and iodine (b moles) .react to give 2x moles of the HI at equilibrium. The total number of moles at equilibrium is

(a)

a+b+2x

(b)

(a-b)+(6-2x)

(c)

(a+b)

(d)

a+b-x

7. For reaction, $2A+B\rightleftharpoons 2C,\quad K=x$ . Equilibrium constant for $C\rightleftharpoons A+1/2B$ will be

(a)

x

(b)

$\cfrac { x }{ 2 }$

(c)

$\cfrac { 1 }{ \sqrt { x } }$

(d)

$\sqrt { x }$

8. In which of the following equilibrium, change in pressure will not affect the equilibrium?

(a)

${ N }_{ 2\left( g \right) }+3{ H }_{ 2\left( g \right) }\rightleftharpoons 2NH_{ 3\left( g \right) }$

(b)

${ H }_{ 2\left( g \right) }+I_{ 2\left( g \right) }\rightleftharpoons 2HI_{ \left( g \right) }$

(c)

${ PCI }_{ 5\left( g \right) }\rightleftharpoons { PCI }_{ 3\left( g \right) }+CI_{ 2\left( g \right) }$

(d)

${ N }_{ 2 }{ O }_{ 4\left( g \right) }\rightleftharpoons 2NO_{ 2\left( g \right) }$

9. ${ C }_{ \left( s \right) }+{ H }_{ 2 }O_{ \left( g \right) }+{ H }_{ 2\left( g \right) }:\Delta H<O$ The above equilibrium will proceed in forward direction when

(a)

It is subjected to high pressure

(b)

It is subjected to high temperature

(c)

Insert gas (argon) is added at constant pressure

(d)

10. Ice and water are placed in a closed container at a pressure of 1 atm and 273.15 K temperature. If pressure of the system is increased by 2 atm keeping temperature constant the correct observation would be

(a)

The amount of ice increases

(b)

Volume of the system increases

(c)

The liquid phase disappears completely

(d)

The solid phase (ice) disappears completely

11. A cylinder filled with a movable piston contains liquid water in equilibrium with water vapour at 25°C. Which one of the following operations results in a decrease in the equilibrium vapour pressure?

(a)

Moving piston downward a short distance

(b)

Removing a small amount of the liquid water

(c)

Dissolving salt in the water

(d)

Removing. a small amount of vapour

12. 2H2(g) +CO2(g) CH30H(g)' $\Delta$H =-92.2 kJ Which of the following condition will shift the equilibrium in the forward direction?

(a)

Temperature of the system is increased

(b)

CO is removed

(c)

(d)

The pressure of the system is increased

13. If Kl is the equilibrium constant at temperature T1 and ~ is the equilibrium constant at temperature T2' and if'T2> T1and reaction is endothermic then

(a)

K2>K1

(b)

K2<K1

(c)

K2=K1

(d)

All of these

14. For the reaction $A+3B\rightleftharpoons 2C+D$ initial mole of A is twice that of B.1f at equilibrium moles of B and C are equal, then percent of B reacted is

(a)

10%

(b)

20%

(c)

40%

(d)

60%

15. For the reaction $CO_{ \left( g \right) }+2H_{ 2\left( g \right) }\rightleftharpoons { CH }_{ 3 }{ OH }_{ \left( g \right) }$ If active mass of CO is kept constant and active mass of H2 is tripled, the rate of forward reaction will become

(a)

Three times

(b)

Six times

(c)

Eight times

(d)

Nine times

16. Statement I: In dissociation of PCI5 to PCl3 and Cl2,Kp> Kc
Statement II : In dissociation of PCI5, ∆ng = -ve and so K, > Kc

(a)

Statement I & II are correct and statement II is the correct explanation of statement 1.

(b)

Statement I & II are correct but statement II is not the correct explanation of statement I.

(c)

Statement I is correct but statement II is wrong

(d)

Statement I is wrong but statement II is correct

17. Which of the following does not alter the equilibrium?

(a)

catalyst

(b)

concentration

(c)

temperature

(d)

pressure

18. Statement I. Addition of an inert gas at constant volume has no effect on equilibrium.
Statement II. When an inert gas is added, the total number of moles of gases present in the container increases and total pressure also increases, the partial pressure of the products and reactants are unchanged.

(a)

Statement I and II are correct but statement II is not the correct explanation of I

(b)

Statement I and II are correct and statement II is the correct explanation of I.

(c)

Statement I is correct but statement II is not correct.

(d)

Statement I is wrong but statement II is correct

19. If dis ociation for reaction PCI5 ⇌ PCl3 + CI2 is 20% at 1 atm pressure. Calculate the value of Kc·

(a)

0.04

(b)

0.05

(c)

0.07

(d)

0.06

20. In the reaction N2 + 3H2 ⇌ 2NH3 + x kCal, one mole of N2 reacts with 3 moles of H2 at equilibrium. Then the value of ∝ (degree of dissociation) is approximately ________. P is the pressure at equilibrium

(a)

$\frac { P\sqrt { 27{ K }_{ P } } }{ 8 }$

(b)

$\frac { 8P }{ { K }_{ P }\sqrt { 27 } }$

(c)

$\frac { P\sqrt { 27 } }{ 8{ K }_{ P } }$

(d)

$\frac{n}{v}$