Ionic Equilibrium PYQs Set 9 (PDF)

Set 9 of 10 · Questions 241-270 of 274

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Ionic Equilibrium · Set 9 (Q241-270)
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241. $The p H value of N /10 NaOH solution is$ (1) $12$ (2) $13$ (3) $10$ (4) $11$ 242. $Which of the following pairs constitutes a buffer?$ (1) $HCl and KCl$ (2) $H N O_{2} and N a N O_{2}$ (3) $NaOH and N a C l$ (4) $H N O_{3} and N H_{4} N O_{3}$ 243. $An acidic buffer is obtained on mixing$ (1) $100 mL of 0.1 M HCl and 200 mL of 0.1 M NaCl$ (2) $100 mL of 0.1 M HCl and 200 mL of 0.1 M CH3COONa$ (3) $100 mL of 0.1 M CH_{3} COOH and 100 mL of 0.1 M NaOH$ (4) $100 mL of 0.1 M CH_{3} COOH and 200 mL of 0.1 M NaOH$ 244. $Which of these is least likely to act as a Lewis base?$ (1) $B F_{3}$ (2) $P F_{3}$ (3) $CO$ (4) $F^{-}$ 245. $The ionic product of water at 2 5^{o} C is 1 0^{- 14} . Its ionic product at 9 0^{o} C will be,$ (1) $1 \times 1 0^{- 14}$ (2) $1 \times 1 0^{- 16}$ (3) $1 \times 1 0^{- 20}$ (4) $1 \times 1 0^{- 12}$ 246. $Which of the following is least likely to behave as Lewis base?$ (1) $H_{2} O$ (2) $N H_{3}$ (3) $B F_{3}$ (4) $O H^{-}$ 247. $Amongst the following, the form of water with the lowest ionic conductance at 298 K is:$ (1) $distilled water$ (2) $sea water$ (3) $water from well$ (4) $saline water used for intravenous injection$ 248. $Which activity from following is exhibited by Lewis base according to definition?$ (1) $accept pair of electron$ (2) $donate a pair of electron$ (3) $accept H^{+} ions$ (4) $donate OH^{-} ions$ 249. $The conjugate base of H_{3} O^{+} is$ (1) $H_{2} O$ (2) $OH^{-}$ (3) $H^{+}$ (4) $H^{-}$ 250. $The K_{a} values of A, B and C are 1.8 \times 10^{- 4}, 5 \times 10^{- 10} and 3 \times 10^{- 8} respectively. The correct order of their acidic strength is$ (1) $B > A > C$ (2) $B > C > A$ (3) $A > B > C$ (4) $A > C > B$ 251. $Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionisation constant of HA is 1 0^{-5}, the ratio of salt to acid concentration in the buffer solution will be :$ (1) $10 : 1$ (2) $4 : 5$ (3) $1 : 10$ (4) $5 : 4$ 252. $The Plot of pH-metric titration of weak base N H_{4} OH vs strong acid HC1 looks like:$ (1) (2) (3) (4) 253. $Class XII students were asked to prepare one litre of buffer solution of pH 8.26 by their chemistry teacher. The amount of ammonium chloride to be dissolved by the student in 0.2 M ammonia solution to make one litre of the buffer is (Given pKb (N H_{3}) = 4.74; Molar mass of N H_{3} = 17 g m o l^{- l}; Molar mass of N H_{4} C1 = 53.5 g m o l^{- 1})$ (1) $53.5 g$ (2) $72.3g$ (3) $107.0g$ (4) $126.0g$ 254. $Equilibrium constant K_{p} for following reaction$ (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) $K_{p} = \frac{P _{M g C O_{3}}}{P _{C O_{2}} \times P _{M g O}}$ 255. $The hydrogen ion concentration of a 1 0^{- 8} M HCl aqueous solution at 298 K_{(} K_{w} = 1 0_{)}^{- 14} is$ (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) $9. 525 \times 1 0^{- 8} M$ 256. $A weak acid, H A, has a K_{a} of 1. 00 \times 1 0^{- 5} . If 0.100 mol ofthis acid is dissolved in one litre of water, the percentage of acid dissociated at equilibrium is closest to$ (1) $1.00%$ (2) $99.9%$ (3) $0.100%$ (4) $99.0%$ 257. $Match List 1 with List II List I (Amines) A. Aniline B. Ethanamine C. N-Ethylethanamine D. N, N-Diethylethanamine List II (p K_{b}) I. 3.25 II. 3.00 III. 9.38 IV. 3.29 Choose the correct answer from the options given below :-$ (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) $A-III, B-IV, C-II, D-I$ 258. $Aqueous solution of acetic acid contains$ (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) $C H_{3} C O O H, C H_{3} C O O^{-} and H^{+}$ 259. $At 8 0^{o} C, distilled water has concentration equal to 1 \times 1 0^{- 6} mole/litre. The value of K_{w} at this temperature will be$ (1) $1 \times 1 0^{- 12}$ (2) $1 \times 1 0^{- 15}$ (3) $1 \times 1 0^{- 6}$ (4) $1 \times 1 0^{- 9}$ 260. $The dissociation constant of a weak acid is 1 \times 1 0^{- 4} . In order to prepare a buffer solution with a p H = 5, the ratio [Salt] / [Acid] should be$ (1) $4:5$ (2) $10:1$ (3) $5:4$ 261. $Given the reaction between 2 gases represented by A_{2} and B_{2} to give the compound A B_{(g)} . A_{2 (g)} + B_{2 (g)} ⇌ 2 A B_{(g)} At equilibrium, the concentration of A_{2} = 3.0 \times 1 0^{- 3} M, of B_{2} = 4.2 \times 1 0^{- 3} M, of A B = 2.8 \times 1 0^{- 3} M If the reaction takes place in a sealed vessel at 52 7^{o} C, then the value of K_{c} will be$ (1) $2.0$ (2) $1.9$ (3) $0.62$ (4) $4.5$ 262. $A buffer solution is prepared in which the concentration of N H_{3} is 0.30 M and the concentration of N H_{4}^{+} is 0.20 M. If the equilibrium constant, K_{b} for N H_{3} equals 1.8 \times 1 0^{- 5}, what is the p H of this solution? (lo g 2.7 = 0.43)$ (1) $9.08$ (2) $9.43$ (3) $11.72$ (4) $8.73$ 263. $Ionisation constant of C H_{3} C O O H is 1.7 \times 1 0^{- 5} and concentration of H^{+} ions is 3. 4 \times 1 0^{- 4} . Then find out initial concentration of C H_{3} C O O H molecules.$ (1) $3.4 \times 1 0^{- 4}$ (2) $3.4 \times 1 0^{- 3}$ (3) $6. 8 \times 1 0^{- 4}$ (4) $6. 8 \times 1 0^{- 3}$ 264. $Which of the following is strongest Bronsted base?$ (1) (2) (3) (4) 265. $A student needs to prepare a buffer solution of propanoic acid and its sodium salt with pH 4. The ratio of \frac{[ CH _{3} CH _{2} COO ^{-} ]}{[ CH _{3} CH _{2} COOH ]} required to make buffer is.......... Given : K_{a} (C H_{3} C H_{2} COOH) = 1.3 x 1 0^{- 5}$ (1) $0.03$ (2) $0.13$ (3) $0.23$ (4) $0.33$ 266. $How many of the following are diprotic acids? Citric acid, Chromic acid, Oxalic acid, Pyrosulfuric acid, Sulfurous acid$ (1) $2$ (2) $5$ (3) $4$ (4) $3$ 267. $The number of species of the following that can act both as Bronsted acids and bases is HCl, ClO_{4}^{-},^{-} OH, H^{+}, H_{2} O, HSO_{4}^{-}, SO_{4}^{2 -}, H_{2} SO_{4}, Cl^{-}$ (1) $4$ (2) $3$ (3) $1$ (4) $2$ 268. $pH value of 0.001 M NaOH solution is______.$ 269. $Total number of non bonded electrons present in NO_{2}^{-} ion based on Lewis theory is$ 270. $At 298 K, the solubility of silver chloride in water is 1.434xlO~^{3} gL'^{1} . The value of - l o g K_{s p} for silver chloride is______. (Given mass of Ag is 107.9 g m o l^{- 1} and mass of Cl is 35.5 g m o l^{- 1})$