Solutions PYQs Set 6 (PDF)

Set 6 of 12 · Questions 151-180 of 332

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Mere Teacher · Previous Year Questions NEET Chemistry · Solutions · Set 6 (Q151-180)
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151. $van't Hoff factor of centimolal solution of K_{3} (Fe (CN)_{6}) is 3.333. Calculate the percent dissociation of K_{3} (Fe (CN)_{6}) .$ (1) $33.33$ (2) $0.78$ (3) $78$ (4) $23.33$ 152. $What is the depression of freezing point, when mole fraction of non-electrolyte solute in aqueous solution is 0.01 ? of$ (1) $1.246 K$ (2) $1.380 K$ (3) $1.528 K$ (4) $1.043 K$ 153. $On mixing urea, the boiling point of H_{2} O changed to 100.5^{\circ} C . Calculate the freezing point of the solution, if K_{f} of water is 1.87 K kg mol^{- 1} and K_{b} of water is 0.52 K kg mol^{- 1} .$ (1) $- 1^{\circ} C$ (2) $- 0.5^{\circ} C$ (3) $- 1.8^{\circ} C$ (4) $0^{\circ} C$ 154. $The molarity of the solution when 4.9 g of H_{2} SO_{4} dissolved in 250 mL of solution is$ (1) $0.1$ (2) $0.2$ (3) $0.3$ (4) $0.4$ 155. $For 1 molal aqueous solution of the following compounds, which one will show the highest freezing point?$ (1) $[Co(H_{2} O)_{4} C l_{2}]Cl. 2 H_{2} O$ (2) $[Co(H_{2} O)_{3} C l_{3}]. 3 H_{2} O$ (3) $[Co (H_{2} O)_{6}] C l_{3}$ (4) $[Co (H_{2} O)_{5} Cl] C l_{2} . H_{2} O$ 156. $Arrange the following solutions in order of their increasing boiling points. (i) 10^{- 4} MNaCl (ii) 10^{- 4} M Urea (iii) 10^{- 3} MNaCl (iv) 10^{- 2} MNaCl$ (1) $(i) < (ii) < (iii) < (iv)$ (2) $(iv) < (iii) < (i) < (ii)$ (3) $(ii) < (i) \equiv (iii) < (iv)$ (4) $(ii) < (i) < (iii) < (iv)$ 157. $Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R: Assertion A: Helium is used to dilute oxygen in diving apparatus. Reasons R: Helium has high solubility in O_{2} In the light of the above statements, choose the correct answer from the options given below:$ (1) $A is false but R is true.$ (2) $Both A and R are true and R is the correct explanation of A .$ (3) $Both A and R are true and R is NOT the correct explanation of A .$ (4) $A is true but R is false.$ 158. $What is the mass of solute having molar mass 60 g mol^{- 1} when dissolved in 98 gram solvent decreases its freezing point by 0.2 K ? (The numerical value of cryoscopic constant of solvent is 1.17 )$ (1) $0.5 gram$ (2) $1.5 gram$ (3) $1.0 gram$ (4) $2.0 gram$ 159. $For which of the following liquid mixtures Δ_{mix} H = 0 and Δ_{mix} V = 0 ?$ (1) $ethyl chloride, ethyl bromide$ (2) $ethanol, acetone$ (3) $phenol, aniline$ (4) $chloroform, acetone$ 160. $Which of the following statements regarding Henry’s law is not correct ?$ (1) $Higher the value of K_{H} at a given pressure, higher is the solubility of the gas in the liquids.$ (2) $Different gases have different K_{H} (Henry’s law constant) values at the same temperature.$ (3) $The partial pressure of the gas in vapour phase is proportional to the mole fraction of the gas in the solution.$ (4) $The value of K_{H} increases with increase of temperature and K_{H} is function of the nature of the gas.$ 161. $31 g of ethylene glycol (C_{2} H_{6} O_{2}) is dissolved in 600 g of water. The freezing point depression of the solution is (K_{f} for water is 1.86 K kg mol^{- 1})$ (1) $0.77 K$ (2) $1.55 K$ (3) $4.65 K$ (4) $3.10 K$ 162. $Liquids and form an ideal solution. The vapour pressure of A and B are 50 and respectively at . One mole of liquid is mixed with of liquid . What is the approximate mole fraction of in vapour phase?$ (1) $0.39$ (2) $0.50$ (3) $0.25$ (4) $0.61$ 163. $Vapour pressure of pure ' ' is of at . It forms an ideal solution with ' ' in which mole fraction of is 0.8 . If the vapour pressure of the solution is of at , the vapour pressure of pure ' ' at is$ (1) $56 mm$ (2) $70 mm$ (3) $140 mm$ (4) $28 mm$ 164. $Equimolar solutions in the same solvent have:$ (1) $same boiling point but different freezing point$ (2) $same freezing point but different boiling point$ (3) $same boiling and same freezing points$ (4) $different boiling and freezing points$ 165. $Which of the following is/are "not correct" for CH_{3} OH + CH_{3} COOH mixture solution? (i) Δ H_{mix} < 0 (ii) Does not obey Raoult's law (iii) Δ H_{mix} > 0 (iv) An example of ideal solution$ (1) $(iv) only$ (2) $(i), (iii) only$ (3) $(i), (ii), (iii) only$ (4) $(iii), (iv) only$ 166. $The osmotic pressure of solution containing 34.2 g of cane sugar (molar mass = 342 g mol^{- 1}) in 1 L of solution at 20^{\circ} C is (Given, R = 0.082 L atm K^{- 1} mol^{- 1})$ (1) $2.40 atm$ (2) $3.6 atm$ (3) $24 atm$ (4) $0.0024 atm$ 167. $At room temperature, a dilute solution of urea is prepared by dissolving 0.60 g of urea in 360 g of water. If the vapour pressure of pure water at this temperature is 35 mm Hg, lowering of vapour pressure will be: (molar mass of urea = 60 g m o l^{- 1})$ (1) $0.027 mmHg$ (2) $0.028 mmHg$ (3) $0.017 mmHg$ (4) $0.031 mmHg$ 168. $K_{2} H g I_{4} is 40% ionised in aqueous solution. The value of its van't Hoff factor (i) is :$ (1) $1.8$ (2) $1.6$ (3) $2.0$ (4) $2.2$ 169. $Which one of the following solutions of compounds show highest osmotic pressure? (AB, A B_{2}) and A_{2} B_{3} are ionic compounds)$ (1) $5.0 M urea i = 1.0 and temperature is 67^{\circ} C$ (2) $1.5 M_{2} B_{3} type i = 4.1 and temperature is 27^{\circ} C$ (3) $3.0 M AB type i = 1.6 and temperature is 27^{\circ} C$ (4) $2.5 MAB B_{2} type i = 2.5 and temperature is 57^{\circ} C$ 170. $The rise in boiling point of a solution containing 1.8 g of glucose in 100 g of solvent is 0.1^{\circ} C . The molal elevation constant of the liquid is$ (1) $2 K kg / mol$ (2) $10 K kg / mol$ (3) $0.1 K kg / mol$ (4) $1 K kg / mol$ 171. $The approximate molarity of a solution in mol L^{- 1} that contains 13.50 g of NaCl dissolved in 452 mL of water is$ (1) $0.25$ (2) $0.51$ (3) $1.0$ (4) $1.2$ 172. $Which of the following aqueous solutions should have the highest boiling point?$ (1) $1, 0 MNaOH$ (2) $1.0 M Na_{2} SO_{4}$ (3) $1.0 M NH_{2} NO_{3}$ (4) $1.0 M KNO_{3}$ 173. $A 0.1 molal aqueous solution of a weak acid is 30% ionized. I f K_{f} for water is 1.8 6^{o} C / m, the freezing point of the solution will be$ (1) $- 0.18 C$ (2) $- 0.54 C$ (3) $- 0.36 C$ (4) $- 0.24 C$ 174. $The number of moles of solute present in the solutions of I, II and III is respectively I. 500 mL of 0.2 MNaOH II. 200 mL of 0.1 N H_{2} SO_{4} III. 6 g of urea in 1 kg of water$ (1) $0.1, 0.01, 0.1$ (2) $0.1, 0.02, 0.1$ (3) $0.2, 0.01, 0.1$ (4) $0.1, 0.01, 0.2$ 175. $The amount of sugar (C_{12} H_{22} O_{11}) required to prepare 2 L of its 0.1 M aqueous solution is:$ (1) $136.8 g$ (2) $17.1 g$ (3) $68.4 g$ (4) $34.2 g$ 176. $A solution containing 6.0 g of urea is isotonic with a solution containing 10 g of a non-electrolytic solute X . The molar mass of X (in g mol^{- 1}) is$ (1) $50.0$ (2) $100$ (3) $75.0$ (4) $68.0$ 177. $Which of the following binary mixture does not show the behaviour of minimum boiling azeotropes?$ (1) $CH_{3} OH + CHCl_{3}$ (2) $C_{6} H_{5} OH + C_{6} H_{5} NH_{2}$ (3) $H_{2} O + CH_{3} COC_{2} H_{5}$ (4) $CS_{2} + CH_{3} COCH_{3}$ 178. $In the depression of freezing point experiment, it is found that : (I) The vapour pressure of the solution is less than that of pure solvent. (II) The vapour pressure of the solution is more than that of pure solvent. (III) Only solute molecules solidify at the freezing point. (IV) Only solvent molecules solidify at the freezing point.$ (1) $I, II$ (2) $II, III$ (3) $I, IV$ (4) $I, II, III.$ 179. $Which of the following are correct for an ideal solution?(A) Δ V_{mix} = 0 (B) V_{solvent} + V_{solute} = V_{solution} (C) Δ H_{mix} = 0 (D) H_{2} O + CO_{2} \to H_{2} CO_{3} is an example of ideal solution.$ (1) $A, B only$ (2) $B, C only$ (3) $A, B, C only$ (4) $a, b, c, d$ 180. $Elevation in the boiling point for 1 molal solution of glucose is 2 k. The depression in the freezing point for 2 molal solution of glucose in the same solvent is 2 k. the relation between k_{b} and K_{f} is_{:}$ (1) $K_{b} = 0. 5 K_{f}$ (2) $K_{b =} K_{f}$ (3) $K_{b =} 1.5 K_{f}$ (4) $k_{b} = 2 k_{f}$