Ionic Equilibrium PYQs Set 3 (PDF)

Set 3 of 10 · Questions 61-90 of 274

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Ionic Equilibrium · Set 3 (Q61-90)
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61. $Observe the following equilibrium Fe^{3 +} (aq) + SCN^{-} (aq) ⇌ [Fe (SCN)]^{2 +} (aq) yellow colourless deep red Addition of aqueous oxalic acid solution to the above equilibrium$ (1) $Shifts the equilibrium towards the formation of [Fe (SCN)]^{2 +}$ (2) $Deep red color increases$ (3) $Intensity of deep red color decreases$ (4) $No change in equilibrium$ 62. $Statement A : pH of buffer increases with increasing temperature. Statement B : The value of K_{W} of water decreases with decreasing temperature.$ (1) $A is correct, but B is wrong.$ (2) $Both A and B are correct$ (3) $Both A and B are wrong$ (4) $A is wrong but B is correct$ 63. $The solubility of AgBr (s), having solubility product 5 \times 10^{- 10} in 0.2 MNaBr solution equals$ (1) $5 \times 10^{- 10} M$ (2) $25\times 1 0^{- 10} M$ (3) $0.5 M$ (4) $0.002 M$ 64. $In which of the following plots, an endothermic reaction is correctly represented?$ (1) (2) (3) (4) 65. $The pH of 10^{- 8} MHCl solution is$ (1) $8$ (2) $-8$ (3) $Between 7-8$ (4) $Between 6-7$ 66. $The solubility of AgCl will be maximum in which of the following?$ (1) $0.01M KCl$ (2) $0.01M HCI$ (3) $0. 01 M A g N O_{3}$ (4) $Deionised water$ 67. $The solubility product for a salt of the type AB is 4 \times 10^{- 8} . What is the molarity of its standard solution?$ (1) $16 \times 10^{- 16} mol / L$ (2) $2 \times 10^{- 16} mol / L$ (3) $4 \times 10^{- 4} mol / L$ (4) $2 \times 10^{- 4} mol / L$ 68. $The ionic product of water\dots\dots.. with increase in temperature.$ (1) $remains constant$ (2) $increases$ (3) $decreases$ (4) $may increase or decrease$ 69. $Which of the following mixture gives a buffer solution with pH = 9.25 ? Given : pK_{b} (NH_{4} OH) = 4.75$ (1) $0.2 MNH_{4} OH (0.5 L) + 0.1 MHCl (0.5 L)$ (2) $0.2 MNH_{4} OH (0.4 L) + 0.1 MHCl (1 L)$ (3) $0.4 MNH_{4} OH (1 L) + 0.1 MHCl (1 L)$ (4) $0.5 MNH_{4} OH (0.2 L) + 0.2 MHCl (0.5 L)$ 70. $What is the order of relative basic strength of ClO_{2}^{-}, ClO_{3}^{-}, ClO_{4}^{-} ?$ (1) $ClO_{2}^{-} > ClO_{3}^{-} > ClO_{4}^{-}$ (2) $ClO_{3}^{-} > ClO_{2}^{-} > ClO_{4}^{-}$ (3) $ClO_{4}^{-} > ClO_{2}^{-} > ClO_{3}^{-}$ (4) $ClO_{2}^{-} > ClO_{4}^{-} > ClO_{3}^{-}$ 71. $Arrange the following in increasing order of solubility product: Ca (OH)_{2}, AgBr, PbS, HgS$ (1) $HgS < AgBr < PbS < Ca (OH)_{2}$ (2) $Ca (OH)_{2} < AgBr < HgS < PbS$ (3) $PbS < HgS < Ca (OH)_{2} < AgBr$ (4) $HgS < PbS < AgBr < Ca (OH)_{2}$ 72. $At T (K), if the ionisation constant of ammonia in solution is 2.5 \times 10^{- 5}, the pH of 0.01 M ammonia solution and the ionisation constant of its conjugate acid respectively at that temperature are (log 2 = 0.30)$ (1) $10.7, 4.0 \times 10^{- 8}$ (2) $10.7, 4.0 \times 10^{- 10}$ (3) $3.3, 4.0 \times 10^{- 8}$ (4) $3.3, 4.0 \times 10^{- 10}$ 73. $If the solubility product of Ni (OH)_{2} is 4.0 \times 10^{- 15} the solubility (in mol L^{- 1}) is$ (1) $5.0 \times 10^{- 5}$ (2) $4.0 \times 10^{- 5}$ (3) $2.0 \times 10^{- 5}$ (4) $1.0 \times 10^{- 5}$ 74. $Consider the following reaction in a 1 L closed vessel. N_{2} + 3 H_{2} ⇌ 2 NH_{3} If all the species; N_{2}, H_{2} and NH_{3} are in 1 mol in the beginning of the reaction and equilibrium is attained after unreacted N_{2} is 0.7 mol . What is the value of equilibrium constant?$ (1) $3600.00$ (2) $3657.14$ (3) $2657.14$ (4) $1828.57$ 75. $The pK_{b} of dimethylamine and pK_{a} of acetic acid are 3.27 and 4.77 respectively at T (K) . The correct option for the pH of dimethylammonium acetate solution is:$ (1) $5.50$ (2) $7.75$ (3) $6.25$ (4) $8.50$ 76. $What is the pH of the NaOH solution when 0.04 g of it dissolved in water and made to 100 mL solution?$ (1) $2$ (2) $1$ (3) $13$ (4) $12$ 77. $Solubility product constant (K_{s p}) of salts of types MX, M X_{2} and M_{3} X at temperature T are 4.0 \times 1 0^{-8}, 3.2 \times 1 0^{-14} and 2.7 \times 1 0^{-15}, respectively. Solubilities (in mol d m^{-3}) of the salts at temperature T are in the order :$ (1) $MX > M X_{2} > M_{3} X$ (2) $M_{3} X > M X_{2} > MX$ (3) $M X_{2} > M_{3} X > MX$ (4) $MX > M_{3} X > M X_{2}$ 78. $Given below are two statements Statement I: The changes in pH with temperature are so small that we often ignore it Statement II: When the hydrogen ion concentration changes by a factor of 100 , the pH changes by one unit In the light of above statements, identify the correct answer from the options given below$ (1) $Both statements I and II are correct.$ (2) $Both statements I and II are not correct.$ (3) $Statement I is correct but statement II is not correct.$ (4) $Statement I is not correct but statement II is correct.$ 79. $What is the equilibrium constant (K_{c}) for the given reaction? N_{2} + O_{2} ⇌ 2 N O Where the equilibrium concentration of N_{2}, O_{2} and NO are found to be 4 \times 10^{- 3}, 3 \times 10^{- 3} and 3 \times 10^{- 3} M respectively.$ (1) $0.750$ (2) $0.622$ (3) $9 \times 10^{- 3}$ (4) $12.8 \times 10^{- 6}$ 80. $Which one of the following information can be obtained on the basis of Le Chatelier principle?$ (1) $Dissociation constant of a weak acid$ (2) $Entropy change in a reaction$ (3) $Equilibrium constant of a chemical reaction$ (4) $Shift in equilibrium position on changing value of a constraint$ 81. $Which of the following happens when NH_{4} OH is added gradually to the solution containing 1 M A^{2 +} and 1 MB^{3 +} ions? Given : K_{sp} (A (OH)_{2}) = 9 \times 10^{- 10} and K_{sp} (B (OH)_{3}) = 27 \times 10^{- 18} at 298 K .$ (1) $Both A (OH)_{2} and B (OH)_{3} do not show$ (2) $A (OH)_{2} will precipitate before B (OH)_{3} precipitation with NH_{4} OH$ (3) $B (OH)_{3} will precipitate before A (OH)_{2}$ (4) $A (OH)_{2} and B (OH)_{3} will precipitate together$ 82. $A solution which is 1 0^{-3} M each in M n^{2 +}, F e^{2 +}, Z n^{2 +} and H g^{2 +} is treated with 1 0^{-16} M sulphide ion. If K_{s p} values of MnS, FeS, ZnS and HgS are 1 0^{-15}, 1 0^{-23}, 1 0^{-20} and 1 0^{-54} respectively, which one will precipitate first?$ (1) $FeS$ (2) $MgS$ (3) $HgS$ (4) $ZnS$ 83. $Calculate the pH of 0.01 M strong dibasic acid.$ (1) $5.5$ (2) $2.5$ (3) $2.0$ (4) $1.7$ 84. $At 400 K, in a 1.0 L vessel, N_{2} O_{4} is allowed to attain equilibrium, N_{2} O_{4} (g) ⇌ 2 NO_{2} (g) At equilibrium, the total pressure is 600 mmHg, when 20 % of N_{2} O_{4} is dissociated. The value of K_{p} for the reaction is$ (1) $50$ (2) $100$ (3) $150$ (4) $200$ 85. $The pH of an aqueous solution containing 1 M benzoic acid (pK_{a} = 4.20) and 1 M sodium benzoate is 4.5 . The volume of benzoic acid solution in 300 mL of this buffer solution is _______mL .$ 86. $The pH at which Mg (OH)_{2} (K_{sp} = 1 \times 10^{- 11}) begins to precipitate from a solution containing 0.10 M Mg^{2 +} ions is_______$ 87. $Sulphurous acid (H_{2} SO_{3}) has Ka_{1} = 1.7 \times 10^{- 2} and Ka_{2} = 6.4 \times 10^{- 8} . The pH of 0.588 MH_{2} SO_{3} is_______(Round off to the Nearest Integer)$ 88. $Two salts A_{2} X and MX have the same value of solubility product of 4.0 \times 10^{- 12} . The ratio of their molar solubilities i.e. \frac{S ( A _{2} X )}{S ( MX )} =________(Round off to the Nearest Integer).$ 89. $The pH of a 0.01 M weak acid HX (K_{a} = 4 \times 10^{- 10}) is found to be 5. Now the acid solution is diluted with excess of water so that the pH of the solution changes to 6. The new concentration of the diluted weak acid is given as x \times 10^{- 4} M . The value of x is (nearest integer)$ 90. $At 310 K, the solubility of C a F_{2} in water is 2.34 x 1 0^{- 3} g /100 mL. The solubility product of C a F_{2} is___x 1 0^{- 8} (m o l / L)^{3} . (Given molar mass : C a F_{2} = 78 g m o l^{- 1})$