Ionic Equilibrium PYQs Set 3 (PDF)

Set 3 of 8 · Questions 61-90 of 233

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Mere Teacher · Previous Year Questions NEET Chemistry · Ionic Equilibrium · Set 3 (Q61-90)
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61. $Which of the following mixture gives a buffer solution with pH = 9.25 ? Given : pK_{b} (NH_{4} OH) = 4.75$ (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) $0.5 MNH_{4} OH (0.2 L) + 0.2 MHCl (0.5 L)$ 62. $What is the order of relative basic strength of ClO_{2}^{-}, ClO_{3}^{-}, ClO_{4}^{-} ?$ (1) $ClO_{2}^{-} > ClO_{3}^{-} > ClO_{4}^{-}$ (2) $ClO_{3}^{-} > ClO_{2}^{-} > ClO_{4}^{-}$ (3) $ClO_{4}^{-} > ClO_{2}^{-} > ClO_{3}^{-}$ (4) $ClO_{2}^{-} > ClO_{4}^{-} > ClO_{3}^{-}$ 63. $Arrange the following in increasing order of solubility product: Ca (OH)_{2}, AgBr, PbS, HgS$ (1) $HgS < AgBr < PbS < Ca (OH)_{2}$ (2) $Ca (OH)_{2} < AgBr < HgS < PbS$ (3) $PbS < HgS < Ca (OH)_{2} < AgBr$ (4) $HgS < PbS < AgBr < Ca (OH)_{2}$ 64. $At T (K), if the ionisation constant of ammonia in solution is 2.5 \times 10^{- 5}, the pH of 0.01 M ammonia solution and the ionisation constant of its conjugate acid respectively at that temperature are (log 2 = 0.30)$ (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) $3.3, 4.0 \times 10^{- 10}$ 65. $If the solubility product of Ni (OH)_{2} is 4.0 \times 10^{- 15} the solubility (in mol L^{- 1}) is$ (1) $5.0 \times 10^{- 5}$ (2) $4.0 \times 10^{- 5}$ (3) $2.0 \times 10^{- 5}$ (4) $1.0 \times 10^{- 5}$ 66. $Consider the following reaction in a 1 L closed vessel. N_{2} + 3 H_{2} ⇌ 2 NH_{3} If all the species; N_{2}, H_{2} and NH_{3} are in 1 mol in the beginning of the reaction and equilibrium is attained after unreacted N_{2} is 0.7 mol . What is the value of equilibrium constant?$ (1) $3600.00$ (2) $3657.14$ (3) $2657.14$ (4) $1828.57$ 67. $The pK_{b} of dimethylamine and pK_{a} of acetic acid are 3.27 and 4.77 respectively at T (K) . The correct option for the pH of dimethylammonium acetate solution is:$ (1) $5.50$ (2) $7.75$ (3) $6.25$ (4) $8.50$ 68. $What is the pH of the NaOH solution when 0.04 g of it dissolved in water and made to 100 mL solution?$ (1) $2$ (2) $1$ (3) $13$ (4) $12$ 69. $Solubility product constant (K_{s p}) of salts of types MX, M X_{2} and M_{3} X at temperature T are 4.0 \times 1 0^{-8}, 3.2 \times 1 0^{-14} and 2.7 \times 1 0^{-15}, respectively. Solubilities (in mol d m^{-3}) of the salts at temperature T are in the order :$ (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) $MX > M_{3} X > M X_{2}$ 70. $Given below are two statements Statement I: The changes in pH with temperature are so small that we often ignore it Statement II: When the hydrogen ion concentration changes by a factor of 100 , the pH changes by one unit In the light of above statements, identify the correct answer from the options given below$ (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) $Statement I is not correct but statement II is correct.$ 71. $What is the equilibrium constant (K_{c}) for the given reaction? N_{2} + O_{2} ⇌ 2 N O Where the equilibrium concentration of N_{2}, O_{2} and NO are found to be 4 \times 10^{- 3}, 3 \times 10^{- 3} and 3 \times 10^{- 3} M respectively.$ (1) $0.750$ (2) $0.622$ (3) $9 \times 10^{- 3}$ (4) $12.8 \times 10^{- 6}$ 72. $Which one of the following information can be obtained on the basis of Le Chatelier principle?$ (1) $Dissociation constant of a weak acid$ (2) $Entropy change in a reaction$ (3) $Equilibrium constant of a chemical reaction$ (4) $Shift in equilibrium position on changing value of a constraint$ 73. $Which of the following happens when NH_{4} OH is added gradually to the solution containing 1 M A^{2 +} and 1 MB^{3 +} ions? Given : K_{sp} (A (OH)_{2}) = 9 \times 10^{- 10} and K_{sp} (B (OH)_{3}) = 27 \times 10^{- 18} at 298 K .$ (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) $A (OH)_{2} and B (OH)_{3} will precipitate together$ 74. $A solution which is 1 0^{-3} M each in M n^{2 +}, F e^{2 +}, Z n^{2 +} and H g^{2 +} is treated with 1 0^{-16} M sulphide ion. If K_{s p} values of MnS, FeS, ZnS and HgS are 1 0^{-15}, 1 0^{-23}, 1 0^{-20} and 1 0^{-54} respectively, which one will precipitate first?$ (1) $FeS$ (2) $MgS$ (3) $HgS$ (4) $ZnS$ 75. $Calculate the pH of 0.01 M strong dibasic acid.$ (1) $5.5$ (2) $2.5$ (3) $2.0$ (4) $1.7$ 76. $At 400 K, in a 1.0 L vessel, N_{2} O_{4} is allowed to attain equilibrium, N_{2} O_{4} (g) ⇌ 2 NO_{2} (g) At equilibrium, the total pressure is 600 mmHg, when 20 % of N_{2} O_{4} is dissociated. The value of K_{p} for the reaction is$ (1) $50$ (2) $100$ (3) $150$ (4) $200$ 77. $The solubility product of Ni (OH)_{2} at 298 K is 2 \times 10^{- 15} mol^{3} dm^{- 9} . The pH value if, its aqueous and saturated solution is$ (1) $5$ (2) $7.5$ (3) $9$ (4) $13$ 78. $At 1000 K, the equilibrium constant. K_{C} for the reaction 2 NOCl (g) ⇌ 2 NO (g) + Cl_{2} (g) is 4.0 \times 10^{- 6} mol L^{- 1} . The K_{p} (in bar) at the same temperature is (R = 0.083 Lbar K^{- 1} mol^{- 1})$ (1) $3.32 \times 10^{- 6}$ (2) $3.32 \times 10^{4}$ (3) $3.32 \times 10^{- 4}$ (4) $3.32 \times 10^{- 3}$ 79. $Following four solutions are prepared by mixing different volumes of NaOH and HCl of different concentrations, pH of which one of the them will be equal to 1?$ (1) $100 mL \frac{M}{10} HCl + 100 mL \frac{M}{10} NaOH$ (2) $75 mL \frac{M}{5} HCl + 25 mL \frac{M}{5} NaOH$ (3) $60 mL \frac{M}{10} HCl + 40 mL \frac{M}{10} NaOH$ (4) $55 mL \frac{M}{10} HCl + 45 mL \frac{M}{10} NaOH$ 80. $On increasing temperature, the equilibrium constant of exothermic and endothermic reactions, respectively$ (1) $increases and decreases$ (2) $decreases and increases$ (3) $increases and increases$ (4) $decreases and decreases$ 81. $Equal volumes of 0.5 N acetic acid and 0.5 N sodium acetate are mixed. What is the pH of resultant solution? (pK_{a}) of acetic acid (= 4.75)$ (1) $4.85$ (2) $4.65$ (3) $4.75$ (4) $7.0$ 82. $An organic monobasic acid has dissociation constant 2.25 \times 10^{- 6} . What is percent dissociation in it's 0.01 M solution?$ (1) $1.5 %$ (2) $15 %$ (3) $5 %$ (4) $0.5 %$ 83. $Solid Ba (N O_{3})_{2} is gradually dissolved in 1.0 \times 1 0^{-4} M N a_{2} C O_{3} solution. At what concentration of B a^{2 +} will a precipitate begin to form ? (K_{s p} for B a C O_{3} = 5.1 \times 1 0^{-9})$ (1) $5.1 \times 1 0^{-5} M$ (2) $8.1 \times 1 0^{-8} M$ (3) $8.1 \times 1 0^{-7} M$ (4) $4.1 \times 1 0^{-5} M$ 84. $K_{P} for the conversion of oxygen to ozone at 400 K is 1.0 \times 10^{- 30}, its standard Gibbs energy change in kJ mol^{- 1} is approximately$ (1) $229.8$ (2) $114.9$ (3) $-229.8$ (4) $-114.9$ 85. $pH of an aqueous solution of NH_{4} Cl is$ (1) $7$ (2) $> 7$ (3) $< 7$ (4) $1$ 86. $100 g of a mixture of NaOH and Na_{2} SO_{4} is neutralised by 100 mL of 0.5 M H_{2} SO_{4} . What is the amount of Na_{2} SO_{4} present in the mixture?$ (1) $82 g$ (2) $96 g$ (3) $88 g$ (4) $92 g$ 87. $Which one of the following statements is not true?$ (1) $Among halide ions, iodide is the most powerful reducing agent.$ (2) $Fluorine is the only halogen that does not show a variable oxidation state.$ (3) $HOCI is a stronger acid than HOBr.$ (4) $HF is a stronger acid than H C l .$ 88. $For the reaction, 0.5 C (s) + 0.5 CO_{2} (g) ⇌ CO (g) the equilibrium pressure is 12 atm . If CO_{2} conversion is 50 %, the value of K_{p}, in atm is$ (1) $4$ (2) $1$ (3) $0.5$ (4) $2$ 89. $Strongest conjugate base among the following is$ (1) $Cl^{-}$ (2) $F^{-}$ (3) $Br^{-}$ (4) $1^{-}$ 90. $The pH of the solution containing 50 mL each of 0.10 M sodium acetate and 0.01 M acetic acid is [Given pK_{a} of CH_{3} COOH = 4.57]$ (1) $2.57$ (2) $5.57$ (3) $3.57$ (4) $4.57$