#### Physical and Chemical Equilibrium Model Question Paper

11th Standard

Reg.No. :
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Chemistry

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. 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

2. Which one of the following is incorrect statement?

(a)

for a system at equilibrium, Q is always less than the equilibrium constant

(b)

equilibrium can be attained from either side of the reaction

(c)

presence of catalyst affects both the forward reaction and reverse reaction to the same extent

(d)

Equilibrium constant varied with temperature

3. 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

4. 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

5. 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

6. 5 x 2 = 10
7. Which of the following reactions involve homogeneous equilibrium and which involve heterogeneous equilibrium?
(i) ${ Ag }_{ 2 }{ O }_{ \left( s \right) }+2HN{ O }_{ 3\left( aq \right) }\rightleftharpoons 2Ag{ NO }_{ 3\left( aq \right) }+{ H }_{ 2 }O$
(ii) ${ C }_{ \left( s \right) }+{ CO }_{ 2\left( g \right) }\rightleftharpoons { 2CO }_{ \left( g \right) }$
(iii) ${ CH }_{ 3 }COO{ C }_{ 2 }{ H }_{ 5\left( aq \right) }+{ H }_{ 2 }{ O }_{ \left( l \right) }\rightleftharpoons { CH }_{ 3 }{ COOH }_{ \left( aq \right) }+{ C }_{ 2 }{ H }_{ 5 }OH_{ \left( aq \right) }$
(iv) ${ 2SO }_{ 2\left( g \right) }+{ O }_{ 2 }\rightleftharpoons { 2SO }_{ 3 }$

8. How will you arrive at the unit of equilibrium constant?

9. Explain how the equilibrium constant Kc predict the extent of a reaction.

10. For the equilibrium 2NOCl(g) ⇄ 2NO(g) + Cl2g) the value of the equilibrium constant Kc is 3.75 x 10-6 at 1069 K. Calculate the Kp for the reaction at this temperature?

11. Equilibrium constant K; for the reaction, N2(g) + 3H2(g)⇌ 2NH3(g) at 500 K is 0.06l. At particular time, the analysis shows that the composition of the reaction mixture is 3.0 mol L-1 of N2; 2.0 mol L-1 of H3; 0.50 mol L-1 of NH3. Is the reaction at equilibrium?

12. 5 x 3 = 15
13. Discuss the equilibrium involving dissolution of solids or gases in liquids.

14. Give the relationship between KP and KC for the follewing cases With example.
(i)  $\Delta { n }_{ g }=+ve$ (ii) $\Delta { n }_{ g }=-ve$ (iii) $\Delta { n }_{ g }=0$

15. Illustrate the formation of solid-vapour equilibrium with suitable example

16. Give three examples for solid vapour equilibrium.

17. Explain the following diagrams
Diagram - I

18. 4 x 5 = 20
19. Explain the effect of concentration, pressure, temperature, catalyst and inert gas on equilibrium.

20. Write a relation between $\triangle$G and Q and define the meaning of each term and answer the following
(i) Why a reaction proceeds forward when Q < K and no net reaction occurs when Q=K?
(ii) Explain the effect of increase in pressure in terms of reaction quotient Q.
For the reaction,
$CO_{(g)}+3H_{2(g)}\rightarrow CH_{4(g)}+H_2O_{(g)}$

21. Derive the values of KC and KP, for the synthesis of Hl.

22. Derive the values of,Kp and Kc for dissociation of PCl5.