Chemical Equilibrium

1. All of the following statements are correct for the EXCEPT:

A) It 1s that stage in reversible reaction, when rate of forward reaction becomes equal to rate of reverse reaction

B) It involves dynamic equilibrium

C) It can establish from either side

D) It is a microscopic propert

2. In which of the following reactions decrease in pressure favours the reaction in reverse direction?

A) Hy+1, 0 2HI

B) PLA PCH, TF BL

C) N, + 3H, ul 2NH4

D) CH;COO0C, Hc + H,0 [1 CH;COOH + C,H:OH

3. Units of Kw are:

A) moldm™3 B) mol?dm™3

C) mol?dm™”° D) mol?dm™3

4. All of the following are applications of Kc EXCEPT:

A) It helps to predict direction of reaction

B) It tells about extent of reaction

C) It tells about rate of reaction

D) It tells about effect of change in concentration, temperature and pressure

5. 0.1 mole of acetic acid is dissolved per dm3 of solution. What is the percentage ionization of acetic acid will be, when Ka value of acetic acid is 4 x 10-5:

A)1.0  B) 1.5

C)2.0  D)2.5

6. For the reactions H2(g) + 12(g) 2HI Kc = 64. If the volume of container is reduced to one fourth of its original volume, the value of Kc will be:

A) 16 B) 32

C) 64 D) 48

7.All of the following is/are characteristic features of solubility product EXCEPT?

A) If solubility 1s known, then Ksp can be calculated

B) If Ksp is known, then solubility can be calculated

C) ltis applicable if the molar concentration of ions is greater than 0.1M

D) The term Ksp is related with reversible process

8. pH of 1.0 mole dm-3 of H2X which is only 50% dissociate:

A)0   B) 1

C)2   D)3

9. Which statement about the following equilibrium is correct? 2502(g) + 02(g) 2503(g) AH=-188.3 kJ mol-1

A) The value of Kp falls with a rise in temp

B) The value of Kp falls with increasing pressure

C) Adding V205 catalyst increases the equilibrium yield of sulphur trioxide

D) The value of Kp is equal to Kc

10. The pH of 10-3 moledm-3 of an aqueous solution of H2S04 is:

A) 3.0   B) 2.7

C)2.0    D) 1.5

11. The solubility product of AgCl is 2.0 x 10-10 mole2 dm-6 . The maximum concentration of Ag+ ions in the solution is:

A)2.0x 107 Ymoldm=3

B) 1.41 x 10 >moldm3

C) 1.0 x 107 Y%omoldm™=3

D) 4.0 x 107° moldm 3

12. When 0.20 moles of hydrogen gas and 0.15 moles of iodine gas are heated at 723 K until equilibrium is established, the equilibrium mixture is found to contain 0.26 moles of hydrogen iodide. The equation for the reaction is as follows: H2(g) + 12(g) 2HI(g) What is the correct expression for the equilibrium constant Kc?

A) 2 x 0.26

B) (0.26)2

C) 0.20 x 0.15 0.07 x 0.02 2×0.26)2 0.26)20) ()

D) (0.26)0.20 x0.150.13x 0.13

13. When 0.20 moles of hydrogen gas and 0.15 moles of iodine gas are heated at 723 Kuntil equilibrium is established, the equilibrium mixture is found to contain 0.26 moles of hydrogen iodide. The equation for the reaction is as follows: H2(g) + 12(g) 2HI(g) What is the correct expression for the equilibrium constant Kc?

A) Ag+ and NO3 -1 only

B) Ag+, Ba2+ and NOS –

C) Ba2+ and NO3 -1 only

D) Ba+2, NO3 -1 and Cl

14. For reaction N2 + 3H2 2NH3:

A) Kc =Kp

B) Kp = Kc RT

C) Kp = Kc (RT)-2

D) Kp = Kc (RT)-1

15. The pH of orange is:

A) 3.5  B) 3.1

C)4.6   D)4.2

16. Which of the following Kc expression is correct for the given reaction?

A) Kc = Fehler!   B) Kc = Fehler!

C) Kc = Fehler!   D) Kc = Fehler!

18. In which of the following reaction Kc value has no unit

A) H,+l, 0 2HI               B) N,+ 3H, [ 2NH,

C) PCL: [1 PCL, + CL,     D) 250, + 0, [1 250;

19. Consider the following reaction 2502 + 02 V205 ,2503 The unit of Kc is:

A) mol dm 3       B) mol™! dm?

C) mol™?% dm? D) mol™? dm®

20. The precipitation occurs if the ionic concentration is

A) Less than Ksp   B) More than Ksp

C) Equal to Ksp     D) None of these

21. For which of the following reactions the numerical value of Kc and Kp is same:

A)N,+3H, [ 2NH,    B) 250, + 0, 0 250;

C) H,+CL, 0 2HCL   D) H,0, U 2NO,

22. One mole of N204 was decomposed according to the given equation in 1dm3 container N204 2NO2. At equilibrium x moles of N204 have dissociated. What is the value of Kc?

A) Fehler!   B) Fehler!

C) Fehler!   D) —Xv(1-x)

23. The Ksp value for PbSO4 is 1.8 x 10-8. The maximum concentration of Pb2+ ion will be:

A)1.8x 1078    B)1×107%

C)1.34×10*      D)1.69x 1078

24. If a buffer solution of CH3COOH and CH3COONa has 1.0 moldm-3 concentration of each, what is pH of buffer solution if pKa value is 4.0?

A) 3.0    B)5

C) 4.0    D)?2

 25. An acid with Ka value less than 10-3 will be:

A) strong acid    B) moderate acid

C) weak acid       D) unpredictable