Ionic Equilibrium PYQs Set 8 (PDF)

Set 8 of 10 · Questions 211-240 of 274

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Ionic Equilibrium · Set 8 (Q211-240)
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211. $Accumulation of lactic acid (H C_{3} H_{5} O_{3}), a monobasic acid in tissues leads to pain and a feeling of fatigue. In a 0.10 M aqueous solution, lactic acid is 3.7% dissociates. The value of dissociation constant, K_{a}, for this acid will be$ (1) $1.4 \times 1 0^{- 5}$ (2) $1.4 \times 1 0^{- 4}$ (3) $3.7 \times 1 0^{- 4}$ (4) $2. 8 \times 1 0^{- 4}$ 212. $An aqueous solution contains an unknown concentration of B a^{2 +} . When 50 mL of a 1M solution of N a_{2} S O_{4} is added, B a S O_{4} just begins to precipitate. The final volume is 500 mL. The solubility product of B a S O_{4} is 1 \times 1 0^{-10} . What is the original concentration of B a^{2 +} .$ (1) $1.1 \times 1 0^{-9} M$ (2) $1.0 \times 1 0^{-10} M$ (3) $5 \times 1 0^{-9} M$ (4) $2 \times 1 0^{-9} M$ 213. $0.1 M solution of which one of these substances will act basic?$ (1) $Sodium borate$ (2) $Ammonium chloride$ (3) $Calcium nitrate$ (4) $Sodium sulphate$ 214. $The dissociation constants for acetic acid and HCN at 25 C are 1. 5 \times 1 0^{- 5} and 4. 5 \times 1 0^{- 10} respectively the equilibrium constant for the equilibrium, would be$ (1) $3.0 \times 1 0^{- 5}$ (2) $3.0 \times 1 0^{- 4}$ (3) $3.0 \times 1 0^{4}$ (4) $3.0 \times 1 0^{5}$ 215. $What is the p H of the resulting solution when equal volumes of 0.1 MNaOH and 0.01 M HCl are mixed?$ (1) $2.0$ (2) $7.0$ (3) $1.04$ (4) $12.65$ 216. $Reaction In equilibrium condition, pressure of O_{2} depends on$ (1) $increase mass of B a O_{2}$ (2) $increase mass of B a O$ (3) $increase temperature on equilibrium$ (4) $increase mass of B a O_{2} and B a O both.$ 217. $If the concentration of O H^{-} ions in the reaction is decreased by 1/4 times, then equilibrium concentration of F e^{3 +} will increase by$ (1) $64 times$ (2) $4 times$ (3) $8 times$ (4) $16 times.$ 218. $At 100 C the K_{w} ofwater is 55 times its value at 2 5^{o} C . What will be the p H ofneutral solution? (lo g 55 = 1.74)$ (1) $7.00$ (2) $7.87$ (3) $5.13$ (4) $6.13$ 219. $Given below are two statements: Statement-I: Methyl orange is a weak acid. Statement-II : The benzenoid form of methyl orange is more intense/deeply coloured than the quinonoid form. In the light of the above statement, choose the most appropriate answer from the options given below:$ (1) $Both Statement-I and Statement-II are incorrect$ (2) $Statement-I is incorrect but Statement-II is correct$ (3) $Both Statement-I and Statement-II are correct$ (4) $Statement-I is correct but Statement-II is incorrect$ 220. $The p H value of a 10 M solution of HCl is$ (1) $equal to 1$ (2) $equal to 2$ (3) $less than 0$ (4) $equal to 0$ 221. $The K_{s p} for the following dissociation is 1.6 \times 1 0^{- 5} : PbC l_{2} (s) ⇌ P b^{2 +} (aq) + 2C l^{-} (aq) . Which of the following choices is correct for a mixture of 300 mL 0.134 M Pb (N O_{3})_{2} and 100 mL 0.4 M HCl ?$ (1) $Q > K_{s p}$ (2) $Q < K_{s p}$ (3) $Q = K_{s p}$ (4) $Not enough data provided$ 222. $K_{s p} for C r (O H)_{3} is 1.6 \times 1 0^{- 30} . What is the molar solubility of this salt in water?$ (1) $\frac{1.8 \times 1 0 ^{- 30}}{27}$ (2) $5 1.8 \times 1 0^{- 30}$ (3) $4 \frac{1.6 \times 1 0 ^{- 30}}{27}$ (4) $2 1.6 \times 1 0^{- 30}$ 223. $The successive equilibrium constants for the stepwise dissociation of a tribasic acid are K_{1}, K_{2} and K_{3} respectively. The equilibrium constant for the overall dissociation is$ (1) $(K_{1} + K_{2} + K_{3})$ (2) $3 (K_{1} + K_{2} + K_{3})$ (3) $(K_{1} \times K_{2} \times K_{3})^{3}$ (4) $K_{1} \times K_{2} \times K_{3}$ 224. $At T (K), the equilibrium constant for the reaction a A (g) ⇌ b B (g) is K_{c} . If the reaction takes place in the following form 2 a A (g) \to 2 b B (g) its equilibrium constant is K_{c}^{'} . The correct relationship between K_{c} and K_{c}^{'} is$ (1) $K_{c}^{'} = K_{c}^{2}$ (2) $K_{c}^{'} = K_{c}^{1/2}$ (3) $K_{c}^{'} = K_{c}^{- 1}$ (4) $K_{c}^{’} = K_{c}$ 225. $The solubility of AgCN in a buffer solution of pH = 3 is x. The value of X is: [Assume: No cyano complex is formed; K_{s p} (AgCN) = 2.2 \times 1 0^{- 16} and K_{a} (HCN) = 6.2 \times 1 0^{- 10}]$ (1) $0.625 \times 10^{- 5}$ (2) $1.6 \times 10^{- 6}$ (3) $2.2 \times 10^{- 16}$ (4) $1.9 \times 10^{- 5}$ 226. $Which has highest p H ?$ (1) $C H_{3} C O O K$ (2) $N a_{2} C O_{3}$ (3) $N H_{4} C I$ (4) $N a N O_{3}$ 227. $Which will make basic buffer?$ (1) $50 mL of 0.1 M NaOH + 25 mL of 0.1 M CH_{3} COOH$ (2) $100 mL of 0.1 M CH_{3} COOH + 100 mL of 0.1 M NaOH$ (3) $100 mL of 0.1 M HCl + 200 mL of 0.1 M NH_{4} OH$ (4) $100 mL of 0.1 M HCl + 100 mL of 0.1 M NaOH$ 228. $Given below are two statements : Statement I : On passing HCl_{(g)} through a saturated solution of BaCl_{2}, at room temperature white turbidity appears. Statement II : When HCl gas is passed through a saturated solution of NaCl, sodium chloride is precipitated due to common ion effect. In the light of the above statements, choose the most appropriate answer from the options given below :$ (1) $Both Statement I and Statement II are correct$ (2) $Statement I is correct but Statement II is incorrect$ (3) $Both Statement I and Statement II are incorrect$ (4) $Statement I is incorrect but Statement II is correct$ 229. $In which of the following reactions at equilibria, the position of the equilibrium shifts towards the products, if the total pressure is increased? (i) X_{2} (g) + 3 Y_{2} (g) ⇌ 2 XY_{3} (g) (ii) X_{2} (g) + Y_{2} (g) ⇌ 2 XY (g) (iii) X_{2} (g) Z_{2} (g) ⇌ 2 XZ (g) (iv) X_{2} (g) + Y_{4} (g) ⇌ 2 XY_{2} (g)$ (1) $(ii)$ (2) $(iii)$ (3) $(i)$ (4) $(iv)$ 230. $Consider the following statements (A) The pH of a mixture containing 400mL of 0.1 M H_{2} SO_{4} and 400mL of 0.1 MNaOH will be approximately 1.3 .(B) Ionic product of water is temperature dependent.(C) A monobasic acid with K_{a} - 10^{- 5} has a pH = 5 The degree of dissociation of this acid is 50%. (D) The Le Chatelier's principle is not applicable to common-ion effect.The correct statements are :$ (1) $(A), (B), and (D)$ (2) $(A), (B) and (C)$ (3) $(B) and (C)$ (4) $(A) and (B)$ 231. $Conjugate acid of N H_{2}^{-} is$ (1) $NHOH$ (2) $N H_{4}^{+}$ (3) $N H_{2}^{-}$ (4) $N H_{3}$ 232. $The solubility products of NiS, ZnS, CdS and HgS are 4.7 \times 10^{- 5}, 1.6 \times 10^{- 24}, 8 \times 10^{- 27} and 4 \times 10^{- 53} respectively. An aqueous solution contains Ni^{2 +}, Zn^{2 +}, Cd^{2 +}, and Hg^{2 +} of equal concentration. H_{2} S gas was passed into this solution very slowly. The first and the last ions that precipitate as sulphides are respectively$ (1) $Ni^{2 +}, Hg^{2 +}$ (2) $Hg^{2 +}, Cd^{2 +}$ (3) $Zn^{2 +}, Hg^{2 +}$ (4) $Hg^{2 +}, Ni^{2 +}$ 233. $(i) H_{3} PO_{4} (aq) ⇌ H^{+} (aq) + H_{2} PO_{4}^{-} (aq) (ii) H_{2} PO_{4}^{-} (aq) ⇌ H^{+} (aq) + HPO_{4}^{2 -} (aq) (iii) HPO_{4}^{2 -} (aq) ⇌ H^{+} (aq) + PO_{4}^{3 -} (aq) The equilibrium constants for the above reactions at a certain temperature are K_{1}, K_{2} and K_{3} respectively. The equilibrium constant for the reaction H_{3} PO_{4} (aq) ⇌ 3 H^{+} (aq) PO_{4}^{-} (aq) in terms of K_{1}, K_{2} and K_{3} is$ (1) $K_{1} + K_{2} + K_{3}$ (2) $\frac{K _{1}}{K _{2} + K _{3}}$ (3) $\frac{K _{3}}{K _{1} K _{2}}$ (4) $K_{1} K_{2} K_{3}$ 234. $Which of the following statement(s) is/are correct? (A) The pH of 1 \times 1 0^{- 8} M HCl solution is 8. (B) The conjugate base of H_{2} P O_{4}^{-} is H P O_{4}^{2 -} (C) K_{w} increases with increase in temperature. (D) When a solution of a weak monoprotic acid is titrated against a strong base at half neutralisation point, pH = \frac{1}{2} p K_{a} . Choose the correct answer from the options given below:$ (1) $(B), (C)$ (2) $(A), (D)$ (3) $(A), (B), (C)$ (4) $(B), (C), (D)$ 235. $For the reaction S O_{2} (g) + \frac{1}{2} O_{2} (g) ⇌ S O_{3} (g), the percentage yield of product at different pressure is shown in the figure. Then, which among the following is true?$ (1) $Pressure has no effect$ (2) $p_{1} < p_{2} < p_{3}$ (3) $p_{1} > p_{2} > p_{3}$ (4) $p_{1} = p_{2} = p_{3} \neq = 0$ 236. $The solubility product of B a S O_{4} is 1 x 1 0^{- 10} at 298 K. The solubility of B a S O_{4} in 0.1M K_{2} S O_{4} (aq) solution is ------ x 1 0^{- 9} g L^{- 1} (nearest integer).Given: Molar mass of B a S O_{4} is 233 g m o l^{- 1}$ 237. $Two solutions, A and B, each of 100 L was made by dissolving 4 g of NaOH and 9.8 g of H_{2} S O_{4} in water, respectively. The pH of the resultant solution obtained from mixing 40 L of solution A and 10 L of solution B is:$ 238. $Consider two Group IV metal ions X^{2 +} and Y^{2 +} . A solution containing 0.01 MX^{2 +} and 0.01 MY^{2 +} is saturated with H_{2} S . The pH at which the metal sulphide YS will form as a precipitate is____. (Nearest integer) (Given: K_{sp} (XS) = 1 \times 10^{- 22} at 25^{\circ} C, K_{sp} (YS) = 4 \times 10^{- 16} at 25^{\circ} C, (H_{2} S) = 0.1 M in solution, K_{a 1} \times K_{a 2} (H_{2} S) = 1.0 \times 10^{- 21}, log 2 = 0.30, log 3 = 0.48, log 5 = 0.70)$ 239. $The molar conductance of an infinitely dilute solution of ammonium chloride was found to be 185 S cm^{2} mol^{- 1} and the ionic conductance of hydroxyl and chloride ions are 170 and 70 S cm^{2} mol^{- 1}, respectively. If molar conductance of 0.02 M solution of ammonium hydroxide is 85.5 S cm^{2} mol^{- 1}, its degree of dissociation is given by x \times 10^{- 1} . The value of x is . (Nearest integer)$ 240. $K_{a} for butyric acid (C_{3} H_{7} C O O H) is 2 \times 1 0^{- 5} . The pH of 0.2 M solution of butyric acid is ___\times 1 0^{- 1} . (Nearest integer) [Given log 2 = 0.30]$