Chemical Equilibrium MCQs – 3

1) The active mass of 64 g of HI in a 2 litre flask would be
a) 0.25
b) 0.50
c) 1.0
d) 2.0

2) The factor that changes the equilibrium constant of the reaction A2(g) + B2(g) 2AB is
a) Total pressure
b)
c) Temperature
d) The presence of a catalyst

3) The reaction that proceeds in the forward direction is
a)
b)
c)
d)

4) The reaction in which the yield of the products can not be increased by the application of high pressure is
a)
b)
c)
d)

5) Which one of the following information can be obtained on the basis of Le Chateliers principle?
a) Shift in equilibrium position on changing certain parameters
b) Dissociation constant of a weak acid
c) Energy change in a reaction
d) Equilibrium constant of a chemical reaction

6) Which of the following will shift the reaction PCl3 + Cl2 PCl5 to the left side?
a)
b) Increase in pressure
c) Decrease in temperature
d) Catalyst

7) In a chemical reaction, equilibrium is said to be established when the
a) Concentration of reactants and products are equal
b) Opposing reactions cease
c) Velocities of the opposing reactions become equal
d) Temperatures of opposing reactions are equal

8) 2SO2+ O2 2SO3 + 47 kcals. If a large excess of oxygen is added to the above system in equilibrium this will
a) Shift the equilibrium to the right
b) Shift the equilibrium to the left
c) Cause no change in the equilibrium
d) Produce only an enormous amount of heat

9) In what manner will an increase in pressure affect the reaction ? C(s) + H2O(g) CO(g) + H2 (g).
a) Shift in the forward direction
b) Shift in the reverse direction
c)
d) No effect

10) A and B are gaseous substances which react reversibly to give two moles of a gaseous product C, accompanied by the liberation of heat. When the reaction reaches equilibrium it was found that Kp = Kc. The equilibrium can not be disturbed by
a) Adding A
b) Adding C
c) Increasing the temperature
d) Increasing the pressure

11) In a chemical equilibrium, the equilibrium constant is found to be 2.5. If the rate constant of backward reaction is 3.2 x 10-2, the rate constant of the forward reaction is
a)
b)
c)
d)

12) On increasing the pressure three fold, the rate of reaction of

2H2S + O2® Products would increase
a) 27 times
b) 9 times
c) 3 times
d) 12 times

13) Kc for A+ B 3C is 20 at 25°C. If a 2 litre vessel contains 1, 2 and 4 moles of A, B and C respectively, the reaction at 25°C shall
a) Proceed from left to right
b) Proceed from right to left
c) Be at equilibrium
d) Not occur

14) Which of the following is least soluble?
a)
b)
c)
d)

15) Which of the following is most soluble in water?
a)
b)
c)
d)

16) Which metal sulphide has the maximum solubility in water?
a)
b)
c)
d)

17) The hydroxide having the lowest value of Ksp at 25°C is
a)
b)
c)
d)

18) The solubility of BaF2 in a solution of Ba(NO3)2 is represented by the concentration term
a)
b)
c)
d)

19) The solubility of Agl in NaI solution is less than that in pure water because
a) AgI forms a complex with NaI
b) Of the common ion effect
c) the solubility product of Agl is less than that of NaI
d) The temperature of the solution decreases

20) The correct representation of the solubility product of SnS2 is
a)
b)
c)
d)

21) When HCl gas is passed through a saturated solution of NaCl, the NaCl is precipitated because
a) The impurities dissolve in HCl
b)
c)
d) The solubility product of NaCl is lowered by the chloride ion from aqueous HCl

22) Precipitation just occurs when the product of the concentration of ions
a) Equals their solubility product
b) Exceeds their solubility product
c) Is less than their solubility product
d) Is negligible.

23) The most soluble salt among the following is
a)
b)
c)
d) All have same solubilities

24) At a certain temperature the value of pKw = 13.4 and the measured pH of a solution is 7. The solution is
a) Acidic
b) Basic
c) Neutral
d) None

25) If the solubility of Ca (OH)2 is 31/2, what will be the solubility product ?
a) 3
b) 27
c)
d)

26) The solubility product of AgCl is 1.44 x 10-4 at 373 K. The solubility of AgCl in boiling water will be
a)
b)
c)
d)

27) Which of the following is most soluble ?
a)
b)
c)
d)

28) The concentration of Ag+ ions in a given saturated solution of AgCl is 1.06x 10 5g ion per litre at 25°C. The solubility product of AgCl is
a)
b)
c)
d)

29) Ksp of AgCl at 18°C is 1.5 x 10-10. If [Ag+] of solution is 4 x 10-3 mole/litre, the the Cl ion concentration that must be exceeded before AgCl is precipitated would be
a) 3.75 x 10 -8 mole/litre
b)
c)
d)

30) A saturated solution of calcium fluoride contains 2 x 10-4 moles of the salt per litre of the solution. Its Ksp is
a)
b)
c)
d)

31) When equal volumes of the following solutions are mixed, precipitation of AgCl (Ksp = 1.8 x 10 10) will occur only with
a)
b)
c)
d)

32) The solubility of AgCl is 0.0015 g/litre. The solubility product of AgCl will be
a) 1.1 x 10-10
b) 2.25 x 10-10
c)
d)

33) The solubility of PbCl2 at 25°C is 6.3 x 10-3 mole/litre. The solubility product of PbCl2 at 25°C is
a)
b)
c)
d)

34) @ How many grams of CaC2O4 will be present in one litre of saturated solution ? Ksp of CaC2O4 is 2.5 x 10-9 mole-2 and its molecular weight is 128
a) 0.0064 g
b) 0.0128 g
c) 0.0032 g
d) 0.0640 g

35) Which solid is less soluble in 0.5 M HCI than in water ?
a)
b)
c)
d) AgI

36) A physician wishes to prepare a buffer solution at pH = 3.58 that efficiently resists a change in pH yet contains only a small concentration of buffering agents. Which one of the following weak acids together with its sodium salt would be best to use ?
a)
b)
c)
d)

37) @ To 100 mL of 0.1 M AgNO3 solution, solid K2SO4 is added. What is the concentration of K2SO4 at which precipitation will start?( Ksp for Ag2SO4 = 6.4x 10-3M)
a) 0.1 M
b) 6.4 x 10-1 M
c)
d)

38) Ksp = [A]3 [B]2 for the salt where A and B are the cation and anion respectively stands true for
a)
b)
c)
d) All

39) Let the solubilities of AgCl in H2O, 0.01 M CaCl2 0.01 M NaCl and 0.05 M AgNO3 be S1, S2, S3 and S4 respectively. What is the correct relationship between these quantities ?
a)
b)
c)
d)

40) A saturated solution of Mg(OH)2 in water at 25°C contains 0.11 g Mg(OH)2 per litre of solution. The solubility product of Mg(OH)2 is
a)
b)
c)
d)

41) Ksp for NaCl is 36 mole2/litre2. The molarity of the saturated solutions is
a) 1/36 M
b) 1/6 M
c) 6 M
d) 3600 M

42) The solubility of PbCl2 in water is 0.01 M at 25°C. Its maximum concentration in 0.1 M NaCl will be
a)
b)
c)
d)

43) The solubility product of a sparingly soluble salt AB at room temperature is 1.21 x 10 6. Its molar solubility is
a)
b)
c)
d)

44) If the solubility product of AgBrO3 and Ag2SO4 are 5.5 x 10-5 and 2 x 10-5 respectively, the relationship between the solubilities of these is
a)
b)
c)
d) None

45) Which of the following solution cannot act as a buffer ?
a)
b)
c)
d)

46) How many milligrams of AgBr will dissolve in water to give 20 litres of aqueous solution ? Ksp for AgBr (mol.wt = 188) = 5.0 x 10 13
a) 2.66 mg
b) 1.33 mg
c) 5.32 mg
d) None

47) The solubility of AgCl is 0.0014 g. per litre at 18°C. What is the solubility product at this temperature. Mol.wt of AgCl is 143.5
a)
b)
c)
d)

48) The solubility of BaSO4 in moles per litre is 1 x 10 -5, its solubility product is
a)
b)
c)
d)

49) What concentration of Ag+ ions will be in equilibrium with a saturated solution containing a precipitate of Ag2CrO4 and CrO4 ion concentration of 0.40 mole per litre? Ksp of Ag2CrO4=1.1×10-11
a)
b)
c)
d)

50) The solubility of SrF2 at 25°C is 1.22 x 10-2 g/litre. What is the solubility product of SrF2 at this temperature ? Mol. wt of SrF2= 125.6 g
a)
b)
c)
d)

51) A solution contains Pb2 + ions. By adding Na2SO4 it is possible to precipitate PbSO4. What concentration is needed to reduce [Pb2+] to 2×10-6 moles per litre ? Ksp of PbSO4 is 1.8×10-8
a)
b)
c)
d) None

52) One litre of a saturated solution of CaCO3 is evaporated to dryness. As a result 7.0 mg of residue is left. What is the solubility product of CaCO3 ?
a)
b)
c)
d)

53) A buffer solution can be prepared from a mixture of
a) Sodium acetate and acetic acid in water
b) Sodium acetate and hydrochloric acid in water
c) Ammonia and hydrochloric acid
d) ammonium chloride and hydrochloric acid

54) Equal volumes of 0.02 M CaCl2 and 0.0004 M Na2SO4 are mixed. Will there be any precipitation? Ksp for CaSO4 = 2.4x 10-5
a) Yes
b) No
c) Unpredictable
d) None

55) In which of the following solvents will AgBr have the highest solubility ?
a)
b) 10-3M NH4OH
c) Pure water
d)

56) If a substance dissolves at saturation with the evolution of heat, the solubility
a) Decreases with an increase in temperature
b) Increases with increase in temperature
c) Does not change
d) None

57) If a substance at saturation dissolves with the absorption of heat, the solubility ….. with an increase in temperature.
a) Decreases
b) Increases
c) Does not change
d) None

58) The solubility of AgCl is 1.435 x 10-3 g/litre. What is the solubility product of AgCl?
Ag = 108, Cl = 35.5.

a)
b)
c)
d)

59) The solubility of AgCl in 0.2 M NaCl solution Rr is which of the following ? Ksp of AgCl = 1.20 x 10-10
a) 0.2M
b)
c)
d)

60) The solubility product of a sparingly soluble salt AB at room temperature is 1.21 x 10-6. Its
molar solubility is

a)
b)
c)
d)

61) The solubility product (Ksp) of CaF2 is 2 x 10-5. The solubility of CaF2 is
a)
b)
c)
d)

62) The conjugate acid of is
a)
b)
c)
d)

63) Which acts both as a Lowry Bronsted acid and base?
a)
b)
c)
d)

64) Among the following, the compound that does not act as a Lewis acid is
a)
b)
c)
d)

65) Which of these is a Lewis acid?
a)
b)
c)
d)

66) In a decinormal solution, CH3COOH is ionised to the extent of 1.3%. If log 1.3 = 0.11, what is the pH of the solution ?.
a) 3.89
b) 2.89
c) 4.89 a
d) 5.89

67) The strongest base among the following is
a)
b)
c)
d)

68)

To a mixture of CH3COOH and CH3COONa, a further amount of CH3COONa is added.

The pH of the mixture
a) Increases
b) Decreases
c) Remains unchanged
d) Unpredictable

69) The equilibrium Cr2O72- CrO42- is shifted to the right in
a) an acidic medium
b) a basic medium
c) a neutral medium
d) It does not exist

70) @ For a reaction, A Products, the rate of reaction doubles when the concentration of A is increased by 4 times. The order of reaction is
a) 4
b) 0
c) 1/2
d) 1

71) The minimum amount of energy required by the reacting molecules at the time of collisions in order to produce effective collisions is called the
a) Activation energy
b) Threshold energy
c) Internal energy
d) Potential energy

72) The chemical reactions in which reactants need a high amount of activation energy are generally
a) Fast
b) Slow
c) Very fast
d) Instantaneous

73) The velocity constant for the forward reaction is 10 and the equilibrium constant is 50. The velocity constant of the backward reaction will be
a) 0.2
b) 2
c) 5
d) 500

74) Raising the temperature of an equilibrium system
a) Favours the exothermic reaction only
b) Favours the endothermic reaction only
c) Favours both the exothermic and endothermic reaction
d) Favours neither the exothermic nor the endothermic reaction

75) Raising the temperature of a reversible chemical reaction
a) Favours the forward rate only
b) Favours the backward rate only
c) Favours either the forward or backward reaction depending upon the sign of DH

d) Favours neither the forward nor backward rates

76) At high altitudes the boiling point of water lowers because the
a) Atmospheric pressure is low
b) Temperature is low
c) Atmospheric pressure is high
d) Water is cold


Answer

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