Chemical Equilibrium PYQs Set 2 (PDF)

Set 2 of 4 · Questions 31-60 of 94

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Mere Teacher · Previous Year Questions NEET Chemistry · Chemical Equilibrium · Set 2 (Q31-60)
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31. $N_{2} + 3 H_{2} ⇌ 2 NH_{3} + heat. What is the effect of the increase of temperature on the equilibrium of the reaction?$ (1) $Equilibrium is unaltered.$ (2) $Reaction rate does not change.$ (3) $Equilibrium is shifted to the left.$ (4) $Equilibrium is shifted to the right.$ 32. $For the equilibrium, CaCO_{3 (s)} ⇌ CaO_{(s)} + CO_{2 (g)}; K_{p} = 1.64 atm at 1000 K 50 g of CaCO_{3} in a 10 litre closed vessel is heated to 1000 K . Percentage of CaCO_{3} that remains unreacted at equilibrium is (Given : R = 0.082 L atm K^{- 1} mol^{- 1})$ (1) $40$ (2) $50$ (3) $60$ (4) $20$ 33. $10^{- 6} MNaOH is diluted 100 times. The pH of the diluted base is$ (1) $between 5 and 6$ (2) $between 6 and 7$ (3) $between 10 and 11$ (4) $between 7 and 8$ 34. $K_{a} values for acids H_{2} SO_{3}, HNO_{2}, CH_{3} COOH and HCN are respectively 1.3 \times 10^{- 2}, 4 \times 10^{- 4}, 1.8 \times 10^{- 5} and 4 \times 10^{- 10}, which of the above acids produce stronger conjugate base in aqueous solution?$ (1) $H_{2} SO_{3}$ (2) $HNO_{2}$ (3) $CH_{3} COOH$ (4) $HCN$ 35. $Consider the following reaction : N_{2} O_{4} (g) ⇌ 2 NO_{2} (g); Δ H^{0} = + 58 kJ For each of the following cases (a, b), the direction in which the equilibrium shifts is:(A) Temperature is decreased (B) Pressure is increased by adding N_{2} at constantT.$ (1) $(A) Towards product, (B) towards reactant$ (2) $(A) Towards reactant, (B) no change$ (3) $(A) Towards reactant, (B) towards product$ (4) $(A) Towards product, (B) no change$ 36. $The value of K_{c} is 64 at 800 K for the reaction N_{2} (g) + 3 H_{2} (g) ⇌ 2 NH_{3} (g) The value of K_{c} for the following reaction is NH_{3} (g) ⇌ \frac{1}{2} N_{2} (g) + \frac{3}{2} H_{2} (g)$ (1) $1/8$ (2) $1/64$ (3) $8$ (4) $1/4$ 37. $Which among the following has highest pH ?$ (1) $1 M H_{2} SO_{4}$ (2) $0.1 M NaOH$ (3) $1 M HCl$ (4) $1 M NaOH$ 38. $For the reaction, 2 SO_{2} (g) + O_{2} (g) ⇌ 2 SO_{3} (g), Δ H = - 57.2 kJ mol^{- 1} and K_{c} = 1.7 \times 10^{16} Which of the following statement is Incorrect?$ (1) $The equilibrium constant is large suggestive of reaction going to completion and so no catalyst is required.$ (2) $The equilibrium will shift in forward direction as the pressure increases.$ (3) $The equilibrium constant decreases as the temperature increases$ (4) $The addition of inert gas at constant volume will not affect the equilibrium constant.$ 39. $A buffer solution contains 0.1 mole of sodium acetate in 1000 cm^{3} of 0.1 M acetic acid. To the above buffer solution, 0.1 mole of sodium acetate is further added and dissolved. The pH of the resulting buffer is equal to$ (1) $p K_{a} - log 2$ (2) $p K_{a}$ (3) $p K_{a} + 2$ (4) $p K_{a} + log 2$ 40. $For the reaction Fe_{2} N (s) + \frac{3}{2} H_{2} (g) ⇌ 2 Fe (s) + NH_{3} (g)$ (1) $K_{C} = K_{p} (RT)^{1/2}$ (2) $K_{C} = K_{p} (RT)$ (3) $K_{C} = K_{p} (RT)^{3/2}$ (4) $K_{C} = K_{p} (RT)^{- 1/2}$ 41. $Which of the following is the strongest base?$ (1) $Cl^{-}$ (2) $OH^{-}$ (3) $CH_{3} O^{-}$ (4) $CH_{3} COO^{-}$ 42. $The yield of the products in the reaction, A_{2 (g)} + 2 B_{(g)} ⇌ C_{(g)} + Q kJ would be higher at$ (1) $high temperature and high pressure$ (2) $high temperature and low pressure$ (3) $low temperature and high pressure$ (4) $low temperature and low pressure.$ 43. $Solubility product of a salt AB is 1 \times 10^{- 8} M^{2} in a solution in which the concentration of A^{+} ions is 10^{- 3} M . The salt will precipitate when the concentration of B^{-} ions is kept$ (1) $between 10^{- 8} M to 10^{- 7} M$ (2) $between 10^{- 7} M to 10^{- 8} M$ (3) $> 10^{- 5} M$ (4) $< 10^{- 8} M .$ 44. $The reaction quotient, ' Q_{c}' is useful in predicting the direction of the reaction. Which of the following is incorrect?$ (1) $If Q_{c} > K_{c}, the reverse reaction is favoured.$ (2) $If Q_{c} < K_{c}, the forward reaction is favoured.$ (3) $If Q_{c} > K_{c}, forward reaction is favoured.$ (4) $If Q_{c} = K_{c}, no reaction occur.$ 45. $Consider the general reaction given below at 400 K x A (g) ⇌ y B (g) The values of K_{p} and K_{c} are studied under the same condition of temperature but variation in x and y . (i) K_{p} = 85.87 and K_{c} = 2.586 appropriate units (ii) K_{p} = 0.862 and K_{c} = 28.62 appropriate units. The values of x and y in (i) and (ii) respectively are: (i) (ii)$ (1) $1,3 2,1$ (2) $4,1 4,1$ (3) $3,1 3,1$ (4) $1,2 2,1$ 46. $Equilibrium constants K_{1} and K_{2} for the following equilibria (1) NO_{(g)} + \frac{1}{2} O_{2 (g)} ⇌ NO_{2 (g)} (2) 2 NO_{2 (g)} ⇌ 2 NO_{(g)} + O_{2 (g)} are related as :$ (1) $K_{1} = K_{2}$ (2) $K_{2} = \frac{1}{K _{1}}$ (3) $K_{1} = 2 K_{2}$ (4) $K_{2} = \frac{1}{K _{1}^{2}}$ 47. $Consider the following reversible chemical reactions: A_{2} (g) + B_{2} (g) ⇌ K_{1} (K_{1}) 2 AB (g) \dots \dots (1) 6 AB (g) ⇌ K_{2} 3 A_{2} (g) + 3 B_{2} (g) \dots .. (2) The relation between K_{1} and K_{2} is:$ (1) $K_{1} K_{2} = \frac{1}{3}$ (2) $K_{2} = K_{1} 3$ (3) $K_{2} = K_{1}^{- 3}$ (4) $K_{1} K_{2} = 3$ 48. $The ratio \frac{K _{p}}{K _{C}} for the reaction : CO_{(g)} + \frac{1}{2} O_{2 (g)} ⇌ CO_{2 (g)} is :$ (1) $\frac{1}{RT}$ (2) $(RT)^{1/2}$ (3) $RT$ (4) $1$ 49. $The pH of the solution obtained by mixing 100 mL of a solution of pH = 3 with 400 mL of a solution of pH = 4 is$ (1) $3 - log 2.8$ (2) $7 - log 2.8$ (3) $4 - log 2.8$ (4) $5 - log 2.8$ 50. $For the given reaction, choose the correct expression of K_{C} from the following :- Fe_{(aq)}^{3 +} + SCN_{(aq)}^{-} ⇌ (FeSCN)_{(aq)}^{2 +}$ (1) $K_{C} = \frac{( FeSCN ^{2 +} )}{( Fe ^{3 +} ) ( SCN ^{-} )}$ (2) $K_{C} = \frac{( Fe ^{3 +} ) [ SCN ^{-} ]}{( FeSCN ^{2 +} )}$ (3) $K_{C} = \frac{( FeSCN ^{2 +} )}{( Fe ^{3 +} ) ^{2} ( SCN ^{-} ) ^{2}}$ (4) $K_{C} = \frac{( FeSCN ^{2 +} ) ^{2}}{( Fe ^{3 +} ) ( SCN ^{-} )}$ 51. $Given below are two statements: Statement I: A catalyst cannot alter the equilibrium constant (K_{c}) of the reaction, temperature remaining constant. Statement II: A homogenous catalyst can change the equilibrium composition of a system, temperature remaining constant. In the light of the above statements, choose the correct answer from the options given below$ (1) $Statement I is true but Statement II is false$ (2) $Statement I is false but Statement II is true$ (3) $Both Statement I and Statement II are true$ (4) $Both Statement I and Statement II are false$ 52. $In a chemical reaction. A + 2 B ⇌ K 2 C + D the initial concentration of B was 1.5 times of the concentration of A but the equilibrium concentrations of A and B were found to be equal. The equilibrium constant (K) for the aforesaid chemical reaction is:$ (1) $4$ (2) $16$ (3) $\frac{1}{4}$ (4) $1$ 53. $Hydroxyl ion concentration of 1 MHCl is$ (1) $1 \times 10^{1} mol dm^{- 3}$ (2) $1 \times 10^{- 13} mol dm^{- 3}$ (3) $1 \times 10^{- 1} mol dm^{- 3}$ (4) $1 \times 10^{- 14} mol dm^{- 3}$ 54. $A weak acid with p K_{a} 5.9 and weak base with p K_{b} 5.8 are mixed in equal proportions. pH of the resulting solution is$ (1) $7.005$ (2) $7.5$ (3) $7$ (4) $7.05$ 55. $2 SO_{2 (g)} + O_{2 (g)} ⇋ V_{2} O_{5} is an example of$ (1) $neutralisation reaction$ (2) $homogeneous catalysis$ (3) $heterogeneous catalysis$ (4) $irreversible reaction.$ 56. $Identify a species which is not a Brönsted acid but a Lewis acid.$ (1) $BF_{3}$ (2) $H_{3} O^{+}$ (3) $NH_{3}$ (4) $HCl$ 57. $Acidity of BF_{3} can be explained on which of the following concepts?$ (1) $Arrhenius concept$ (2) $Bronsted-Lowry concept$ (3) $Lewis concept$ (4) $Bronsted-Lowry as well as Lewis concept$ 58. $5 mL of 0.4 NNaOH is mixed with 20 mL of 0.1 NHCl . The pH of the resulting solution will be$ (1) $6$ (2) $7$ (3) $8$ (4) $5$ 59. $For the given hypothetical reactions, the equilibrium constants are as follows : X ⇌ Y; K_{1} = 1.0 Y ⇌ Z; K_{2} = 2.0 Z ⇌ W; K_{3} = 4.0 The equilibrium constant for the reaction X ⇌ W is$ (1) $6.0$ (2) $12.0$ (3) $7.0$ (4) $8.0$ 60. $Consider the reaction N_{2} (g) + 3 H_{2} (g) ⇌ 2 NH_{3} (g) The equilibrium constant of the above reaction is K_{P} pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given by (Assume that P_{NH_{3}} << P_{total} at equilibrium)$ (1) $\frac{3 ^{3/2} K _{P}^{1/2} P ^{2}}{16}$ (2) $\frac{K _{P}^{1/2} P ^{2}}{16}$ (3) $\frac{K _{P}^{1/2} P ^{2}}{4}$ (4) $\frac{3 ^{3/2} K _{P}^{1/2} P ^{2}}{4}$