#### Physical and Chemical Equilibrium Book Back Questions

11th Standard

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Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
5 x 1 = 5
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. In the equilibrium,
2A(g) ⇌ 2B(g) + C2(g)
the equilibrium concentrations of A, B and C2 at 400 K are 1 × 10–4 M, 2.0 × 10–3 M, 1.5 × 10–4 M respectively. The value of KC for the equilibrium at 400 K is

(a)

0.06

(b)

0.09

(c)

0.62

(d)

3 x 10-2

4. An equilibrium constant of 3.2 × 10–6 for a reaction means, the equilibrium is

(a)

largely towards forward direction

(b)

largely towards reverse direction

(c)

never established

(d)

none of these

5. 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)

6. 4 x 2 = 8
7. For a given reaction at a particular temperature, the equilibrium constant has constant value. Is the value of Q also constant? Explain.

8. What the relation between KP and KC. Give one example for which KP is equal to KC.

9. For a gaseous homogeneous reaction at equilibrium, number of moles of products are greater than the number of moles of reactants. Is KC is larger or smaller than KP.

10. Explain how will you predict the direction of a equilibrium reaction.

11. 4 x 3 = 12
12. The value of Kc for the following reaction at 717 K is 48.

13. The value of Kc for the reaction

14. For an equilibrium reaction Kp = 0.0260 at 25° C ΔH= 32.4 kJmol-1, calculate Kp at 37° C

15. Oxidation of nitrogen monoxide was studied at 200o C with initial pressures of 1 atm NO and 1 atm of O2. At equilibrium partial pressure of oxygen is found to be 0.52 atm calculate KP value.

16. 1 x 5 = 5
17. 1 mol of PCl5, kept in a closed container of volume 1 dm3 and was allowed to attain equilibrium at 423 K. Calculate the equilibrium composition of reaction mixture. (The Kc value for PCl5 dissociation at 423 K is 2)