Chemical Equilibrium - II One Mark Questions

1. 2H2O(g)+2Cl2(g) ⇌ 4HCl(g)+5O2(g), the value of Kp and Kc are related as

a) Kp = Kc            b) Kp > Kc                  c) Kp < Kc                  d) Kp = Kc = 0.

2. For a homogenous gaseous reaction at 600K 4NH3(g)+5O2(g)⇌ 4NO(g)+6H2O(g) the equilibrium constant Kc has the unit

a) (mol dm^-3)^–1       b) mol dm^-3                  c) (mol dm^-3)⁴              d) (mol dm^-3)^–2 

3. For / In an endothermic equilibrium reaction, if K1 and K2 are the equilibrium constants at T1 and T2 temperatures respectively and if T2 is greater than / T2 > T1, then

a) K1 < K2            b) K1>K2                    c) K1 = K2                  d) None /

a) K1 is less than K2                                 b) K1 is greater than K2

c) K1 is equal to K2                                  d) None of these.

4. Forward reaction takes place, when

a) Q < kc               b) Q > kc                     c) Q = kc                     d) kc = 1/Q

5. H2(g) + I2(g)  ⇌ 2 HI(g) The equilibrium constant Kc for this reaction is 16. Kp value is

a) 1 / 16                 b) 4                              c) 64                            d) 16.

6. If the equilibrium constant for the formation of a product is 25, the equilibrium constant for the decomposition of the same product is

a) 25                      b) 1 / 25                       c) 5                              d) 625.

7. If the equilibrium constants of the following reactions 2A  ⇌ B is K1 and B  ⇌ 2A is K2, then

a) K1 = 2K2          b) K1 = 1 / K2             c) K2 = (K1)²              d) K1 = 1 / K2²

8. In a reaction 2O3  ⇌ 3O2 the value of Kc is

a) [O3]3 / [O2]2    b) [O2]2 / [O3]3          c) [O2]3 / [O3]2          d) [O3] / [O2]

9. In the equilibrium N2 + 3H2  ⇌ 2NH3 / In the manufacture of ammonia by Haber's process,  the maximum yield of ammonia will be obtained with the process having

a) low pressure and high temperature       b) low pressure and low temperature

c) high temperature and high pressure      d) high pressure and low temperature.

10. In the Haber process the yield of ammonia is greater

a) at high pressure                                     b) at low pressure

c) at high temperature                               d) in absence of catalyst.

11. In the reversible reaction 2HI(g)  ⇌ H2(g) + I2(g), Kp is

a) greater than Kc             b) less than Kc            c) equal to Kc              d) 0 / zero.

12. In the synthesis of NH3 between N2 and H2 reaction the unit of Kc is

a) lit² mol^–2            b) atm^–2                       c) lit atm^–1                   d) atm- l

13. State of a chemical equilibrium is

a) dynamic            b) stationary                c) both (a) and (b)       d) none of these

14. The equilibrium constant for the reaction 2A ⇌ B is 25 mol-1 dm3 at 900 K. What is the equilibrium constant for the reaction B  2A in dm-3 mol at the same temperature?

a) 25                      b) 625                          c) 0.04                         d) 0.4.

15. The fraction of total moles of reactant dissociated is called

a) dissociation equilibrium                        b)degree of association

c) degree of dissociation                           d) dissociation constant.

16. The maximum yield of ammonia by Haber’s process is

a) 78%                   b) 97%                         c) 37%                         d) 89%

17. The optimum temperature used in  contact process for the manufacture of SO3 is

a) 400°C to 450°C                                    b) 1800°C to 2700°C

c) 500°C to 550°C                                    d) 350°C to 450°C

18. The rate constant of forward and reverse reactions are 8 × 10-5 and 2 × 10-4 respectively. The value of Kc is

a) 0.04                   b) 0.02                         c) 0.2                           d) 0.4

19. The relationship between Kp and Kc for the equilibrium 2H2O(g)+2Cl2(g)  ⇌ 4HCl(g)+ O2(g) is

a) Kp = Kc            b) Kp = Kc(RT)2        c) Kp = Kc(RT)1         d) Kp = Kc(RT)^–2.

20. Two moles of ammonia gas are introduced into a previously evacuated 1.0 dm3 vessel in which it partially dissociates at high temperature. At equilibrium 1.0 mole of ammonia remains. The equilibrium constant Kc for the dissociation is

a) 27 / 16 (mole dm-3)2                            b) 27 / 8 (mole dm-3)2

c) 27 / 4 (mole dm-3)2                              d) none of these

21. When Δng in a homogenous gaseous equilibrium is positive, then

a) Kp = Kc            b) Kp > Kc                  c) Kc > Kp                  d) Kp = 2Kc /
a) Kp = Kc            b) Kp < Kc                  c) Kp > Kc                  d) Kp = Kc/ 2

22. Which of the following gaseous equilibria is favoured by increase in temperature?

a) N2O4 ⇌ 2NO2; ΔH = + 59 kJ mol–1

b) N2+3H2 ⇌  2NH3; ΔH = -22 kcalmol^–1

c) 2SO2+O2 ⇌  2SO3; ΔH = - 47 k cal mol^–1 

d) Both (b) and (c).

23. Which one of the following has negative value for Δng?

a) H2(g)+ I2(g) ⇌ 2HI(g)                    b) PCl5(g) ⇌ PCl3(g) + Cl2(g)

c) 3H2(g) + N2(g) ⇌ 2NH3(g)            d) 2H2O(g) + 2Cl2(g) ⇌ 4HCl(g) + O2(g).
24. In an equilibrium reaction, Q < kc then
a) forward reaction is favoured                                b) reverse reaction is favoured
c) both forward and reverse reaction is favoured      d) none of these

25. In which of the following gaseous reactions Kp < Kc?

a) PCl5(g) ⇌ PCl3(g) + Cl2(g)               b) H2(g)+ I2(g) ⇌ 2HI(g) 
c) N2(g) + 3H2(g) ⇌ 2NH3(g)                d) CO(g) + 2H2O(g) ⇌ CO2(g) + H2(g)

26. The equilibrium constant Kc for the reaction A(g) ⇌ B(g)  is 2.5 x 10^–2. The rate constant of forward reaction is 0.05 sec^–1. Therefore, the rate constant of reverse reaction is

a) 2 seconds^–1         b) 0.2 seconds^–1            c) 2 minutes^–1            d) 0.2 minutes^–1.

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