Chemical Equilibrium PYQs Set 4 (PDF)

Set 4 of 5 · Questions 91-120 of 138

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Chemical Equilibrium · Set 4 (Q91-120)
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91. $In a chemical reaction, A + 2B ⇌ K 2C+D, the initial concentration of B was 1.5 times of the concentration of A, but the equilibrium concentrations of A and B were found to be equal. The equilibrium constant (K) for the aforesaid chemical reaction is :$ (1) $16$ (2) $1$ (3) $1/4$ (4) $4$ 92. $In the Figure shown below reactant A (represented by square) is an equilibrium with product B (represented by circle). The equilibrium constant is:$ (1) $4$ (2) $8$ (3) $1$ (4) $2$ 93. $5.1 g N H_{4} SH is introduced in 3.0 L evacuated flask at 327°C. 30% of the solid N H_{4} SH decomposed to N H_{3} and H_{2} S as gases. The K_{p} of the reaction at 327°C is (R = 0.082 L atm m o l^{-1} K^{-1}, molar mass of S = 32 g m o l^{-1}, molar mass of N = 14 g m o l^{-1})$ (1) $4.9 \times 1 0^{-3} a t m^{2}$ (2) $0.242 \times 1 0^{-4} a t m^{2}$ (3) $1 \times 1 0^{-4} a t m^{2}$ (4) $0.242 a t m^{2}$ 94. $At a certain temperature in a 5 L vessel, 2 moles of carbon monoxide and 3 moles of chlorine were allowed to reach equilibrium according to the reaction, CO + C l_{2} ⇌ C O C l_{2} At equilibrium if one mole of CO is present then equilibrium constant K_{C} for reaction is$ (1) $2$ (2) $2.5$ (3) $3$ (4) $4$ 95. $For a concentrated solution of a weak electrolyte (K_{e q} =equilibrium constant) A_{2} B_{3} of concentration 'C', the degree of dissociation ' α' is$ (1) $(\frac{K _{e q}}{5 c ^{4}})^{\frac{1}{5}}$ (2) $(\frac{K _{e q}}{108 c ^{4}})^{\frac{1}{5}}$ (3) $(\frac{K _{e q}}{25 c ^{2}})^{\frac{1}{5}}$ (4) $(\frac{K _{e q}}{6 c ^{5}})^{\frac{1}{5}}$ 96. $Which of the following lines correctly show the temperature dependence of equilibrium constant, K, for an exothermic reaction$ (1) $C and D$ (2) $A and D$ (3) $A and B$ (4) $B and C$ 97. $For a reaction at equilibrium A (g) ⇌ B (g) + \frac{1}{2} C (g) the relation between dissociation constant (K), degree of dissociation (^{α}) and equilibrium pressure (p) is given by :$ (1) $K = \frac{α ^{\frac{1}{2}} p ^{\frac{3}{2}}}{( 1 + \frac{3}{2} α ) ^{\frac{1}{2}} ( 1 - α )}$ (2) $K = \frac{α ^{\frac{3}{2}} p ^{\frac{1}{2}}}{( 2 + α ) ^{\frac{1}{2}} ( 1 - α )}$ (3) $K = \frac{( α p ) ^{\frac{3}{2}}}{( 1 + \frac{3}{2} α ) ^{\frac{1}{2}} ( 1 - α )}$ (4) $K = \frac{( α p ) ^{\frac{3}{2}}}{( 1 + α ) ( 1 - α ) ^{\frac{1}{2}}}$ 98. $The relationship between K_{p} and K_{c} is K_{p} = K_{c} (R T)^{Δ n} . What would be the value of Δ n for the reaction, N H_{4} C l_{(s)} ⇌ N H_{3 (g)} + H C l_{(g)} ?$ (1) $1$ (2) $0.5$ (3) $1.5$ (4) $2$ 99. $For the reaction A_{(g)} + B_{(g)} ⇌ C_{(g)} + D_{(g)}; Δ H = - Q kJ The equilibrium constant cannot be disturbed by$ (1) $addition of A$ (2) $addition of D$ (3) $none of the above$ (4) $increasing of temperature.$ 100. $Consider the following gaseous equilibrium in a closed container of volume ' V ' at T (K) . P_{2} (g) + Q_{2} (g) ⇌ 2 PQ (g) 2 moles each of P_{2} (g), Q_{2} (g) and PQ (g) are present at equilibrium. Now one mole each of ' P_{2}' and ' Q_{2}' are added to the equilibrium keeping the temperature at T (K) . The number of moles of P_{2}, Q_{2} and PQ at the new equilibrium, respectively, are$ (1) $1.66, 1.66, 1.66$ (2) $2.56, 1.62, 2.24$ (3) $2.67, 2.67, 2.67$ (4) $1.21, 2.24, 1.56$ 101. $Consider the equilibrium CO (g) + 3 H_{2} (g) ⇌ CH_{4} (g) + H_{2} O (g) If the pressure applied over the system increases by two fold at constant temperature then (A) Concentration of reactants and products increases. (B) Equilibrium will shift in forward direction. (C) Equilibrium constant increases since concentration of products increases. (D) Equilibrium constant remains unchanged as concentration of reactants and products remain same. Choose the correct answer from the options given below :$ (1) $(A), (B) and (C) only$ (2) $(A) and (B) only$ (3) $(A), (B) and (D) only$ (4) $(B) and (C) only$ 102. $K a_{1}, K a_{2} and K a_{3} are the respective ionization constants for the following reactions (A),(B), and (C). (A) H_{2} C_{2} O_{4} H^{+} + H C_{2} O_{4}^{-} (B) H_{2} C_{2} O_{4}^{-} H^{+} + H C_{2} O_{4}^{2 -} (C) H_{2} C_{2} O_{4} 2 H^{+} + C_{2} O_{4}^{2 -} The relationship between K_{a 1}, K_{a 2} and K_{a 3} is given as$ (1) $K_{a_{3}} = K_{a_{1}} + K_{a_{2}}$ (2) $K_{a_{3}} = K_{a_{1}} - K_{a_{2}}$ (3) $K_{a_{3}} = K_{a_{1}} / K_{a_{2}}$ (4) $K_{a_{3}} = K_{a_{1}} \times K_{a_{2}}$ 103. $For reaction : S O_{2} (g) + \frac{1}{2} O_{2} (g) ⇌ S O_{3} (g) K_{P} = 2 x 1 0^{12} at 27°C and 1 atm pressure. The K_{c} for the same reaction is_______^{x} 1 0^{13} (Nearest integer)$ 104. $Water decomposes at 2300 K H_{2} O (g) \to H_{2} (g) + \frac{1}{2} O_{2} (g) The percent of water decomposing at 2300 K and 1 bar is (Nearest integer). Equilibrium constant for the reaction is 2 x 1 0^{- 3} at 2300 K$ 105. $Consider the following reaction approaching equilibrium at 27°C and 1 atm pressure A + B K_{r} = 1 0^{2} ⇄ K_{f} = 1 0^{3} C + D The standard Gibb's energy change (∆_{r} G°) at 27°C is (-)_______kJ m o l^{- 1} (Nearest integer).$ 106. $The number of moles of NH3, that must be added to 2L of 0.80M AgNO3in order to reduce the concentration of Ag^{+} ions to 5.0x 1 0^{- 8} M (K formation for [A g (N H_{3})_{2}]^{+} =1. 0 x 1 0^{8}) is ____.(Nearest integer) [Assume no volume change on adding NH3]$ 107. $The equilibrium constant K_{c} at 298K for the reaction A + B ⇌ C + D is 100. Starting with an equimolar solution with concentrations of A, B, C and D all equal to 1M, the equilibrium concentration of D is ____ x10-2M. (Nearest integer)$ 108. $The equilibrium composition for the reaction P C 1_{3} + C 1_{2} P C 1_{5} at 298 K is given below: [P C l_{3}]_{e q} = 0.2mol L^{- 1}, [C l_{2}]_{e q} = 0.1 mol L^{- 1}, [P C l_{6}]_{e q} = 0.40 mol L^{- 1} If 0.2 mol of Cl2 is added at the same temperature, the equilibrium concentrations of P C l_{5} is_____x 1 0^{- 2} mol L^{- 1} Given: K_{c} for the reaction at 298 K is 20$ 109. $4.5 moles each of hydrogen and iodine is heated in a sealed ten litre vessel. At equilibrium, 3 moles of HI were found. The equilibrium constant for H_{2} (g)+ I_{2} (g) 2 H I_{(g)} is........$ 110. $At 298 K N_{2} (g) + 3 H_{2} (g) ⇌ 2 N H_{3} (g), K_{1} = 4 x 1 0^{5} N_{2} (g) + O_{2} (g) ⇌ 2NO(g), K_{2} =1. 6 x 1 0^{12} H_{2} (g) + \frac{1}{2} O_{2} (g) ⇌ H_{2} O(g), K_{3} =1. 0 x 1 0^{- 13} Based on above equilibria, the equilibrium constant of the reaction, 2 N H_{3} (g) + \frac{5}{2} O_{2} (g) ⇌ 2NO (g) + 3 H_{2} O (g) is___x 1 0^{- 33} (Nearest integer)$ 111. $The standard free energy change for 50% dissociation of N_{2} O_{4} into N O_{2} at 27°C and 1 atm pressure is -x J moH. The value of x is _________. (Nearest Integer)[Given : R = 8.31 J K^{- 1} m o l^{- 1}, log 1.33 = 0.1239 In 10 = 2.3]$ 112. $When 5.1 g of solid N H_{4} HS is introduced into a two litre evacuated flask at 2 7^{\circ} C, 20% of the solid decomposes into gaseous ammonia and hydrogen sulphide. The K_{p} for the reaction at 2 7^{\circ} C is x \times 1 0^{- 2} . The value of x is ____. (Integer answer) [Given R = 0.082 L atm K^{- 1} mo l^{- 1}]$ 113. $37.8 g N_{2} O_{5} was taken in a 1L reaction vessel and allowed to undergo the following reaction bat 500 K 2 N_{2} O_{5 (g)} ⇌ 2 N_{2} O_{4 (g)} + O_{2 (g)} The total pressure at equilibrium was found to be 18.65 bar. Then, Kp = \times 10^{- 2} [nearest integer] Assume N_{2} O_{5} to behave ideally under these conditions. Given: R = 0.082 bar Lmol^{- 1} K^{- 1}$ 114. $The equilibrium constant for decomposition of H_{2} O (g) H_{2} O (g) ⇌ H_{2} (g) + \frac{1}{2} O_{2} (g) (Δ G^{\circ} = 92.34 kJ) mol^{- 1}) is 8.0 \times 10^{- 3} at 2300 K and total pressure at equilibrium is 1 bar. Under this condition, the degree of dissociation (α) of water is \times 10^{- 2} (nearest integer value). [Assume α is negligible with respect to 1]$ 115. $Consider the following equilibrium, C O (g) + 2 H_{2} (g) ⇌ CH_{3} OH (g) 0.1 mol of CO along with a catalyst is present in a 2 dm^{3} flask maintained at 500 K. Hydrogen is introduced into the flask until the pressure is 5 bar and 0.04 mol of CH_{3} OH is formed. The K_{p}^{θ} is \times 10^{- 3} (nearest integer). Given: R = 0.08 dm^{3} bar K^{- 1} mol^{- 1} Assume only methanol is formed as the product and the system follows ideal gas behavior.$ 116. $Dissociation of a gas A_{2} takes place according to the following chemical reaction. At equilibrium, the total pressure is 1 bar at 300 K. A_{2} (g) ⇌ 2 A (g) The standard Gibbs energy of formation of the involved substances has been provided below: Substance Δ G_{f}^{\circ} / kJ mol^{- 1} A_{2} -100.00 A -50.832 The degree of dissociation of A_{2} (g) is given by (x \times 10^{- 2})^{1/2} where x =____. (Nearest integer). [Given: R = 8 J mol^{- 1} K^{- 1}, log 2 = 0.3010, log 3 = 0.48] Assume degree of dissociation is not negligible.$ 117. $At 298 K, the equilibrium constant is 2 x 1015 for the reaction: Cu (s) + 2 A g^{+} (aq) C u^{2 +} (aq) + 2 Ag (s) The equilibrium constant for the reaction \frac{1}{2} C u^{2 +} (aq) + Ag (s) \frac{1}{2} Cu (s) + A g^{+} (aq) is x \times 10-8. The value of x is _______. (Nearest Integer)$ 118. $The stepwise formation of [Cu (N H_{3})^{2 +} is given below: C u^{2 +} + N H_{3} K_{1} (Cu (N H_{3})_{4})^{2 +} (Cu (N H_{3})_{2})^{2 +} + N H_{3} K_{2} (Cu (N H_{3})_{2})^{2 +} (Cu (N H_{3})_{2})^{2 +} + N H_{3} k_{3} = (Cu (N H_{3})_{3})^{2 +} (Cu (N H_{3})_{3})^{2 +} + N H_{3} K_{4} (Cu (N H_{3})_{4})^{2 +} The value of stability constants K_{1}, K_{2}, K_{3} and K_{4} are 10^{4}, 1.58 \times 10^{2}, 5 \times 10^{2} and 10^{2} respectively. The overall equilibrium constants for dissociation of (Cu (N H_{3})_{4})^{2 +} is x \times 10^{- 12} . The value of x is ____. (Rounded off to the nearest integer)$ 119. $X_{2} (g) + Y_{2} (g) ⇌ 2 Z (g) X_{2} (g) and Y_{2} (g) are added to a 1 L flask and it is found that the system attains the above equilibrium at T (K) with the number of moles of X_{2} (g), Y_{2} (g) and Z (g) being 3,3 and 9 mol respectively (equilibrium moles). Under this condition of equilibrium, 10 mol of Z (g) is added to the flask and the temperature is maintained at T (K) . Then the number of moles of Z (g) in the flask when the new equilibrium is established is____. (Nearest integer)$ 120. $For the following gas phase equilibrium reaction at constant temperature, NH_{3} (g) ⇌ 1/2 N_{2} (g) + 3/2 H_{2} (g) if the total pressure is 3 atm and the pressure equilibrium constant (K_{p}) is 9 atm , then the degree of dissociation is given as (x \times 10^{- 2})^{- 1/2} . The value of x is____(nearest integer)$