Ionic Equilibrium PYQs Set 8 (PDF)

Set 8 of 8 · Questions 211-233 of 233

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Mere Teacher · Previous Year Questions NEET Chemistry · Ionic Equilibrium · Set 8 (Q211-233)
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211. $The conjugate base of H_{3} O^{+} is$ (1) $H_{2} O$ (2) $OH^{-}$ (3) $H^{+}$ (4) $H^{-}$ 212. $The K_{a} values of A, B and C are 1.8 \times 10^{- 4}, 5 \times 10^{- 10} and 3 \times 10^{- 8} respectively. The correct order of their acidic strength is$ (1) $B > A > C$ (2) $B > C > A$ (3) $A > B > C$ (4) $A > C > B$ 213. $Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionisation constant of HA is 1 0^{-5}, the ratio of salt to acid concentration in the buffer solution will be :$ (1) $10 : 1$ (2) $4 : 5$ (3) $1 : 10$ (4) $5 : 4$ 214. $The Plot of pH-metric titration of weak base N H_{4} OH vs strong acid HC1 looks like:$ (1) (2) (3) (4) 215. $Class XII students were asked to prepare one litre of buffer solution of pH 8.26 by their chemistry teacher. The amount of ammonium chloride to be dissolved by the student in 0.2 M ammonia solution to make one litre of the buffer is (Given pKb (N H_{3}) = 4.74; Molar mass of N H_{3} = 17 g m o l^{- l}; Molar mass of N H_{4} C1 = 53.5 g m o l^{- 1})$ (1) $53.5 g$ (2) $72.3g$ (3) $107.0g$ (4) $126.0g$ 216. $Equilibrium constant K_{p} for following reaction$ (1) $K_{p} = P_{C O_{2}}$ (2) $K_{p} = P_{C O_{2}} \times \frac{P _{C O_{2}} \times P _{M g O}}{P _{M g C O_{3}}}$ (3) $K_{p} = \frac{P _{C O_{2}} + P _{M g O}}{P _{M g C O_{3}}}$ (4) $K_{p} = \frac{P _{M g C O_{3}}}{P _{C O_{2}} \times P _{M g O}}$ 217. $The hydrogen ion concentration of a 1 0^{- 8} M HCl aqueous solution at 298 K_{(} K_{w} = 1 0_{)}^{- 14} is$ (1) $1. 0 \times 1 0^{- 8} M$ (2) $1. 0 \times 1 0^{- 6} M$ (3) $1. 0525 \times 1 0^{- 7} M$ (4) $9. 525 \times 1 0^{- 8} M$ 218. $A weak acid, H A, has a K_{a} of 1. 00 \times 1 0^{- 5} . If 0.100 mol ofthis acid is dissolved in one litre of water, the percentage of acid dissociated at equilibrium is closest to$ (1) $1.00%$ (2) $99.9%$ (3) $0.100%$ (4) $99.0%$ 219. $Match List 1 with List II List I (Amines) A. Aniline B. Ethanamine C. N-Ethylethanamine D. N, N-Diethylethanamine List II (p K_{b}) I. 3.25 II. 3.00 III. 9.38 IV. 3.29 Choose the correct answer from the options given below :-$ (1) $A-I, B-IV, C-II, D-III$ (2) $A-III, B-II, C-I, D-IV$ (3) $A-III, B-II, C-IV, D-I$ (4) $A-III, B-IV, C-II, D-I$ 220. $Aqueous solution of acetic acid contains$ (1) $C H_{3} C O O^{-} and H^{+}$ (2) $C H_{3} C O O^{-}, H_{3} O^{+} and C H_{3} C O O H$ (3) $C H_{3} C O O^{-}, H_{3} O^{+} and H^{+}$ (4) $C H_{3} C O O H, C H_{3} C O O^{-} and H^{+}$ 221. $At 8 0^{o} C, distilled water has concentration equal to 1 \times 1 0^{- 6} mole/litre. The value of K_{w} at this temperature will be$ (1) $1 \times 1 0^{- 12}$ (2) $1 \times 1 0^{- 15}$ (3) $1 \times 1 0^{- 6}$ (4) $1 \times 1 0^{- 9}$ 222. $The dissociation constant of a weak acid is 1 \times 1 0^{- 4} . In order to prepare a buffer solution with a p H = 5, the ratio [Salt] / [Acid] should be$ (1) $4:5$ (2) $10:1$ (3) $5:4$ 223. $Given the reaction between 2 gases represented by A_{2} and B_{2} to give the compound A B_{(g)} . A_{2 (g)} + B_{2 (g)} ⇌ 2 A B_{(g)} At equilibrium, the concentration of A_{2} = 3.0 \times 1 0^{- 3} M, of B_{2} = 4.2 \times 1 0^{- 3} M, of A B = 2.8 \times 1 0^{- 3} M If the reaction takes place in a sealed vessel at 52 7^{o} C, then the value of K_{c} will be$ (1) $2.0$ (2) $1.9$ (3) $0.62$ (4) $4.5$ 224. $A buffer solution is prepared in which the concentration of N H_{3} is 0.30 M and the concentration of N H_{4}^{+} is 0.20 M. If the equilibrium constant, K_{b} for N H_{3} equals 1.8 \times 1 0^{- 5}, what is the p H of this solution? (lo g 2.7 = 0.43)$ (1) $9.08$ (2) $9.43$ (3) $11.72$ (4) $8.73$ 225. $Ionisation constant of C H_{3} C O O H is 1.7 \times 1 0^{- 5} and concentration of H^{+} ions is 3. 4 \times 1 0^{- 4} . Then find out initial concentration of C H_{3} C O O H molecules.$ (1) $3.4 \times 1 0^{- 4}$ (2) $3.4 \times 1 0^{- 3}$ (3) $6. 8 \times 1 0^{- 4}$ (4) $6. 8 \times 1 0^{- 3}$ 226. $Which of the following is strongest Bronsted base?$ (1) (2) (3) (4) 227. $A student needs to prepare a buffer solution of propanoic acid and its sodium salt with pH 4. The ratio of \frac{[ CH _{3} CH _{2} COO ^{-} ]}{[ CH _{3} CH _{2} COOH ]} required to make buffer is.......... Given : K_{a} (C H_{3} C H_{2} COOH) = 1.3 x 1 0^{- 5}$ (1) $0.03$ (2) $0.13$ (3) $0.23$ (4) $0.33$ 228. $How many of the following are diprotic acids? Citric acid, Chromic acid, Oxalic acid, Pyrosulfuric acid, Sulfurous acid$ (1) $2$ (2) $5$ (3) $4$ (4) $3$ 229. $The number of species of the following that can act both as Bronsted acids and bases is HCl, ClO_{4}^{-},^{-} OH, H^{+}, H_{2} O, HSO_{4}^{-}, SO_{4}^{2 -}, H_{2} SO_{4}, Cl^{-}$ (1) $4$ (2) $3$ (3) $1$ (4) $2$ 230. $If α is dissociation constant, then the total number of moles for the reaction, 2 H I \to H_{2} + I_{2} will be$ (1) $1$ (2) $1 - α$ (3) $2$ (4) $2 - α$ 231. $Which one of the following is correct?$ (1) $The equilibrium constant K_{C} is independent of temperature.$ (2) $The value of K_{C} is independent of initial concentrations of reactants and products.$ (3) $At equilibrium, the rate of the forward reaction is twice the rate of the backward reaction.$ (4) $The equilibrium constant (K_{c}) for the reaction. Ni (s) + 4 CO (g) ⇌ Ni (CO)_{4} (g) is, \frac{( Ni ( CO ) _{4} )}{[ CO ]} .$ 232. $When the hydrogen ion concentration [H^{+}] changes by a factor of 1000, the value of pH of the solution$ (1) $increases by 1000 units$ (2) $decreases by 3 units$ (3) $decreases by 2 units$ (4) $increases by 2 units$ 233. $Ammonia is a Lewis base because it is$ (1) $Electron pair donor$ (2) $Electron pair acceptor$ (3) $Proton donor$ (4) $Proton acceptor$