Chemical Equilibrium PYQs Set 3 (PDF)

Set 3 of 5 · Questions 61-90 of 138

In the print window choose “Save as PDF”. The file prints without a web address or date line.

Mere Teacher · Previous Year Questions JEE Main Chemistry · Chemical Equilibrium · Set 3 (Q61-90)
Scan or visit mereteacher.com for free PYQ practice, timed CBT tests, step-by-step solutions and BroBot AI. Answers and solutions are free with a sign-up.
61. $The ratio \frac{K _{p}}{K _{C}} for the reaction : CO_{(g)} + \frac{1}{2} O_{2 (g)} ⇌ CO_{2 (g)} is :$ (1) $\frac{1}{RT}$ (2) $(RT)^{1/2}$ (3) $RT$ (4) $1$ 62. $The pH of the solution obtained by mixing 100 mL of a solution of pH = 3 with 400 mL of a solution of pH = 4 is$ (1) $3 - log 2.8$ (2) $7 - log 2.8$ (3) $4 - log 2.8$ (4) $5 - log 2.8$ 63. $For the given reaction, choose the correct expression of K_{C} from the following :- Fe_{(aq)}^{3 +} + SCN_{(aq)}^{-} ⇌ (FeSCN)_{(aq)}^{2 +}$ (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) $K_{C} = \frac{( FeSCN ^{2 +} ) ^{2}}{( Fe ^{3 +} ) ( SCN ^{-} )}$ 64. $Given below are two statements: Statement I: A catalyst cannot alter the equilibrium constant (K_{c}) of the reaction, temperature remaining constant. Statement II: A homogenous catalyst can change the equilibrium composition of a system, temperature remaining constant. In the light of the above statements, choose the correct answer from the options given below$ (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) $Both Statement I and Statement II are false$ 65. $In a chemical reaction. A + 2 B ⇌ K 2 C + D the initial concentration of B was 1.5 times of the concentration of A but the equilibrium concentrations of A and B were found to be equal. The equilibrium constant (K) for the aforesaid chemical reaction is:$ (1) $4$ (2) $16$ (3) $\frac{1}{4}$ (4) $1$ 66. $Hydroxyl ion concentration of 1 MHCl is$ (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) $1 \times 10^{- 14} mol dm^{- 3}$ 67. $A weak acid with p K_{a} 5.9 and weak base with p K_{b} 5.8 are mixed in equal proportions. pH of the resulting solution is$ (1) $7.005$ (2) $7.5$ (3) $7$ (4) $7.05$ 68. $2 SO_{2 (g)} + O_{2 (g)} ⇋ V_{2} O_{5} is an example of$ (1) $neutralisation reaction$ (2) $homogeneous catalysis$ (3) $heterogeneous catalysis$ (4) $irreversible reaction.$ 69. $Identify a species which is not a Brönsted acid but a Lewis acid.$ (1) $BF_{3}$ (2) $H_{3} O^{+}$ (3) $NH_{3}$ (4) $HCl$ 70. $Acidity of BF_{3} can be explained on which of the following concepts?$ (1) $Arrhenius concept$ (2) $Bronsted-Lowry concept$ (3) $Lewis concept$ (4) $Bronsted-Lowry as well as Lewis concept$ 71. $5 mL of 0.4 NNaOH is mixed with 20 mL of 0.1 NHCl . The pH of the resulting solution will be$ (1) $6$ (2) $7$ (3) $8$ (4) $5$ 72. $For the given hypothetical reactions, the equilibrium constants are as follows : X ⇌ Y; K_{1} = 1.0 Y ⇌ Z; K_{2} = 2.0 Z ⇌ W; K_{3} = 4.0 The equilibrium constant for the reaction X ⇌ W is$ (1) $6.0$ (2) $12.0$ (3) $7.0$ (4) $8.0$ 73. $Consider the reaction N_{2} (g) + 3 H_{2} (g) ⇌ 2 NH_{3} (g) The equilibrium constant of the above reaction is K_{P} pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given by (Assume that P_{NH_{3}} << P_{total} at equilibrium)$ (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) $\frac{3 ^{3/2} K _{P}^{1/2} P ^{2}}{4}$ 74. $Observe the following equilibrium in a 1 L flask. A (g) ⇌ B (g) At T (K), the equilibrium concentrations of A and B are 0.5 M and 0.375 M respectively. 0.1 moles of A is added into the flask and heated to T (K) to establish the equilibrium again. The new equilibrium concentrations (in M) of A and B are respectively$ (1) $0.53, 0.4 .$ (2) $0.742, 0.557 .$ (3) $0.557, 0.418 .$ (4) $0.367, 0.275 .$ 75. $Consider the following gaseous equilibria with equilibrium constants K_{1} and K_{2} respectively. SO_{2 (g)} + \frac{1}{2} O_{2 (g)} ⇌ SO_{3 (g)} 2 SO_{3 (g)} ⇌ 2 SO_{2 (g)} + O_{2 (g)} The equilibrium constants are related as$ (1) $K_{1}^{2} = \frac{1}{K _{2}}$ (2) $2 K_{1} = K_{2}^{2}$ (3) $K_{2} = \frac{2}{K _{1}^{2}}$ (4) $K_{2}^{2} = \frac{1}{K _{1}}$ 76. $1 mole of HI is heated in a closed container of capacity of 2 L . At equilibrium half a mole of HI is dissociated. The equilibrium constant of the reaction is$ (1) $0.25$ (2) $0.35$ (3) $1$ (4) $0.5$ 77. $5 moles of SO_{2} and 5 moles of O_{2} are allowed to react. At equilibrium, it was found that 60 % of SO_{2} is used up. If the partial pressure of the equilibrium mixture is one atmosphere, the partial pressure of O_{2} is$ (1) $0.52 atm$ (2) $0.21 atm$ (3) $0.41 atm$ (4) $0.82 atm$ 78. $In presence of HCl, H_{2} S results the precipitation of group-2 elements but not group-4 elements during qualitative analysis. It is due to$ (1) $higher concentration of H^{+}$ (2) $lower concentration of H^{+}$ (3) $higher concentration of S^{2 -}$ (4) $lower concentration of S^{2 -}$ 79. $The values of K_{p} / K_{c} for the following reactions at 300 K are, respectively: (At 300 K, RT = 24.62 dm^{3} atm mol^{- 1}) N_{2} (g) + O_{2} (g) ⇌ 2 NO (g) N_{2} O_{4} (g) ⇌ 2 NO_{2} (g) N_{2} (g) + 3 H_{2} (g) ⇌ 2 NH_{3} (g)$ (1) $1,24.62dm3atm mol^{- 1}, 606.0 dm^{6} atm^{2} mol^{- 2}$ (2) $1, 24.62 dm^{3} atm mol^{- 1}, 1.65\times 1 0^{- 3} dm-6atm-2mol2$ (3) $1, 4.1 \times 10^{- 2} dm^{- 3} atm^{- 1} mol, 606 dm^{6} atm^{2} mol^{- 2}$ (4) $24.62 dm^{3} atm mol^{- 1}, 606.0 dm^{6} atm^{2} mol^{- 2}, 1.65 \times 10^{- 3} dm^{- 6} atm^{- 2} mol^{2}$ 80. $At temperature T, compound AB_{2 (g)} dissociates as AB_{2 (g)} ⇌ AB_{(g)} + \frac{1}{2} B_{2 (g)} having degree of dissociation x (small compared to unity). The correct expression for x in terms of K_{p} and p is$ (1) $4 \frac{2 K _{p}}{p}$ (2) $3 \frac{2 K _{p}}{p}$ (3) $3 \frac{2 K _{p}^{2}}{p}$ (4) $K_{p}$ 81. $The effect of addition of helium gas to the following reaction in equilibrium state, is : P C I_{5} (g) ⇌ P C l_{3} (g) + C l_{2} (g)$ (1) $the equilibrium will shift in the forward direction and more of C l_{2} and P C l_{3} gases will be produced.$ (2) $the equilibrium will go backward due to suppression of dissociation of P C 1_{5} .$ (3) $helium will deactivate P C l_{5} and reaction will stop.$ (4) $addition of helium will not affect the equilibrium.$ 82. $4 moles each of SO_{2} and O_{2} gases are allowed to react to form SO_{3} in a closed vessel. At equilibrium 25 % of O_{2} is used up. The total number of moles of all the gases at equilibrium is$ (1) $6.5$ (2) $7.0$ (3) $8.0$ (4) $2.0$ 83. $4.0 moles of argon and 5.0 moles of P C I_{5} are introduced into an evacuated flask of 100 litre capacity at 610 K. The system is allowed to equilibrate. At equilibrium, the total pressure of mixture was found to be 6.0 atm. The K_{p} for the reaction is [Given : R = 0.082L atm K^{- 1} m o l^{- 1}]$ (1) $2.25$ (2) $6.24$ (3) $12.13$ (4) $15.24$ 84. $At 600K, 2 mol of NO are mixed with 1 mol of O_{2} . 2 N O_{(g)} + O_{2} (g) 2 N O_{2} (g) The reaction occurring as above comes to equilibrium under a total pressure of 1 atom. Analysis of the system shows that 0.6 mol of oxygen are present at equilibrium. The equilibrium constant for the reaction is _______. (Nearest integer).$ 85. $A homogeneous ideal gaseous reaction A B_{2_{(g)}} ⇌ A_{(g)} + 2 B_{(g)} is carried out in a 25 litre flask at 27°C. Theinitial amount of AB_{2} was 1 mole and the equilibrium pressure was 1.9 atm. The value of K_{p} is x \times 10^{- 2} . Thevalue of x is _____(R = 0.08206 dm^{3} atm K^{- 1} mol^{- 1})$ 86. $At 1990 K and 1atrm pressure, there are equal number of Cl_{2} molecules and Cl atoms in the reaction mixture. The value of K_{p} for the reaction Cl_{2 (g)} = 2 Cl_{(g)} under the above conditions is x \times 10^{- 1} . The value of x is____. (Rounded off to the nearest integer)$ 87. $The following concentrations were observed at 500 K for the formation of NH_{3} from N_{2} and H_{2} . At equilibrium : (N_{2}) = 2 \times 10^{- 2} M, (H_{2}) = 3 \times 10^{- 2} M and (NH_{3}) = 1.5 \times 10^{- 2} M . Equilibrium constant for the reaction is_______$ 88. $(i)X(g) ⇌ Y(g) + Z(g) K_{p 1} = 3 (ii) A(g) ⇌ 2B(g) K_{p 2} = 1 If the degree of dissociation and initial concentration of both the reactants X(g) and A(g) are equal, then the ratio of the total pressure at is equal to x : 1, The value of x is ________(Nearest integer)$ 89. $PC l_{5} ⇌ PC l_{3} + C l_{3} K_{C} = 1.844 3.0 moles of P C l_{5} is introduced in a 1L closed reaction vessel at 380K. The number of moles of P C l_{5} at equilibrium \times 1 0^{- 3} is (Round off to the Nearest Integer)$ 90. $A mixture of one mole of H_{2} O and 1 mole of CO is taken in a 10 litre container and heated to 725 K. At equilibrium 40% of water by mass reacts with carbon monoxide according to the equation: CO(g) + H_{2} O(g) C O_{2} (g) + H_{2} (g). The equilibrium constant K_{C} x 1 0^{2} for the reaction is________(Nearest integer)$