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

11th Standard

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Chemistry

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

Answer all the questions

20 x 1 = 20
1. If Kb and Kf for a reversible reactions are 0.8 ×10–5 and 1.6 × 10–4 respectively, the value of the equilibrium constant is,

(a)

20

(b)

0.2 x 10-4

(c)

0.05

(d)

none of these

2. Solubility of carbon dioxide gas in cold water can be increased by

(a)

increase in pressure

(b)

decrease in pressure

(c)

increase in volume

(d)

none of these

3. K1 and K2 are the equilibrium constants for the reactions respectively.
${ N }_{ 2 }(g)+{ O }_{ 2 }(g)\overset { { K }_{ 1 } }{ \rightleftharpoons } 2NO(g)$
$2NO(g)+{ O }_{ 2 }(g)\overset { { K }_{ 2 } }{ \rightleftharpoons } { 2NO }_{ 2 }(g)$
What is the equilibrium constant for the reaction NO2(g) ⇌ ½N2(g) + O2(g)

(a)

${1\over \sqrt{K_1K_2}}$

(b)

(K1 = K2)1/2

(c)

${1\over 2K_1K_2}$

(d)

$({1\over K_1K_2})^{3/2}$

4. Equimolar concentrations of H2 and I2 are heated to equilibrium in a 1 litre flask. What percentage of initial concentration of Hhas reacted at equilibrium if rate constant for both forward and reverse reactions are equal

(a)

33%

(b)

66%

(c)

(33)2%

(d)

16.5%

5. A 20 litre container at 400 K contains CO2 (g) at pressure 0.4 atm and an excess of SrO (neglect the volume of solid SrO). The volume of the container is now decreased by moving the movable piston fitted in the container. The maximum volume of the container, when pressure of CO2 attains its maximum value will be:
Given that: SrCO3 (S) ⇌ SrO (S) + CO2(g)
KP = 1.6 atm

(a)

2 litre

(b)

5 litre

(c)

10 litre

(d)

4 litre

6. In which of the following does the reaction go almost to completion?

(a)

Kc = 103

(b)

Kc = 102

(c)

Kc = 10-2

(d)

Kc= 10-3

7. XY2 dissociates as,$XY_{ 2\left( g \right) }\rightleftharpoons { XY }_{ \left( g \right) }+Y_{ \left( g \right) }$ Initial pressure of XY2 is 600mm Hg. The total pressure at equilibrium is 800mm Hg. Assuming volume of system to remain constant, the value of Kp is

(a)

50

(b)

100

(c)

400

(d)

20

8. In melting of ice, which one of the conditions will be more favorable?

(a)

high temperature and high pressure

(b)

low temperature and low pressure

(c)

low temperature and high pressure

(d)

high temperature and low pressure

9. A state of equilibrium is reached when

(a)

The rate of forward reaction is greater than the rate of the reverse reaction

(b)

The concentration of the products and reactants are equal

(c)

More product is present than rea

(d)

The concentration of the products and reactants have reached constant value

10. The numerical, value of equilibrium constant depends on

(a)

temperature

(b)

pressure

(c)

concentration of reactants

(d)

all of these

11. The favourable conditions for melting of ice is

(a)

Low pressure

(b)

High pressure

(c)

Low temperature

(d)

Absence of catalyst

12. The value of AH for the reaction
${ X }_{ 2\left( g \right) }+4Y_{ 2\left( g \right) }\rightleftharpoons 2XY_{ 4\left( g \right) }$ is less than zero. Formation of XY4(g) will be favoured at :

(a)

High pressure and low temperature

(b)

Low pressure and low temperature

(c)

High temperature and high pressure

(d)

High temperature and low pressure.

13. The value of equilibrium constant of the reaction,
${ HI }_{ \left( g \right) }\rightleftharpoons \cfrac { 1 }{ 2 } { H }_{ 2\left( g \right) }+\cfrac { 1 }{ 2 } { I }_{ 2\left( g \right) }$ is 8.0. The equilibrium constant of the reaction; ${ H }_{ 2\left( g \right) }+I_{ 2\left( g \right) }\rightleftharpoons { 2HI }_{ \left( g \right) }$

(a)

$\cfrac { 1 }{ 8 }$

(b)

$\cfrac { 1 }{ 16 }$

(c)

16

(d)

$\cfrac { 1 }{ 64 }$

14. In the manufacture of NH3 by Haber's process involving the reaction.${ N }_{ 2\left( g \right) }+{ 3H }_{ 2\left( g \right) }\overset { \left[ { Fe }_{ 2 }{ O }_{ 2 } \right] }{ \rightleftharpoons } 2{ NH }_{ 3\left( g \right) }$ $\Delta H$=-22.08 kcal. The favourable conditions are

(a)

High pressure and low temperature

(b)

High pressure and high temperature

(c)

Low pressure and high temperature

(d)

Low pressure and low temperature

15. Sulphide ion reacts with solid sulphur
${ S }_{ \left( aq \right) }^{ 2- }+{ S }_{ \left( s \right) }\rightleftharpoons { S }_{ 2\left( aq \right) }$ K1=10
${ S }_{ \left( aq \right) }^{ 2- }+{ 2S }_{ \left( s \right) }\rightleftharpoons { S }_{ 3\left( aq \right) }$ K2=130
The equilibrium constant for the formation of ${ S }_{ 3 }^{ 2- }\left( aq \right)$ and ${ S }_{ 2 }^{ 2- }\left( aq \right)$

(a)

10

(b)

13

(c)

130

(d)

1300

16. The active mass of 7.0 g of nitrogen in a 2.0 L container would be

(a)

0.25

(b)

0.125

(c)

0.5

(d)

14.0

17. Equilibrium constant Kp for following reaction
$MgCO_{ 3\left( s \right) }\rightleftharpoons Mg{ O }_{ \left( s \right) }+{ CO }_{ 2\left( g \right) }$

(a)

Kp = Pco2

(b)

${ K }_{ p }=\cfrac { { p }_{ { CO }_{ 2 } }\times { p }_{ CO_{ 2 } }\times { p }_{ Mgo } }{ { P }_{ MrCO } }$

(c)

${ K }_{ p }=\cfrac { { P }_{ MG }{ CO }_{ 3 } }{ { P }_{ CO\bullet }p_{ mgO } }$

(d)

${ K }_{ p }=\cfrac { { P }_{ MG }{ CO }_{ 3 } }{ { P }_{ CO\bullet }p_{ mgO } }$

18. In the system;$Fe\left( OH \right) _{ 3\left( s \right) }\rightleftharpoons { Fe }_{ \left( aq \right) }^{ 3+ }+{ 3OH }_{ \left( aq \right) }$ decreasing the conc. of OH-ions $\cfrac { 1 }{ 3 } ^{ - }$times will cause the equilibrium cone, of Fe3+ to increase .... times

(a)

27

(b)

9

(c)

18

(d)

3

19. For the homogeneous gas reaction at 600K $4NH_{ 3\left( g \right) }+5{ O }_{ 2\left( g \right) }\rightleftharpoons 4NO_{ \left( g \right) }+6{ H }_{ 2 }{ O }_{ \left( g \right) }$ The equilibrium Kc has the unit.

(a)

(mol dm-3)-1

(b)

(mol dm-3)1

(c)

(mol dm-3)10

(d)

(mol dm-3)9

20. Which one of the following equation is not correct?

(a)

∆Go = - RTlnK

(b)

∆Go = ∆Ho -T∆So

(c)

-RTlnK = ∆Ho -T∆So

(d)

ln k=$\frac { \Delta { H }^{ o } }{ T } -\frac { \Delta { S }^{ o } }{ R }$