Solutions PYQs Set 13 (PDF)

Set 13 of 14 · Questions 361-390 of 419

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Solutions · Set 13 (Q361-390)
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361. $A solution is prepared by dissolving 0.3 g of a non-volatile non-electrolyte solute ' A ' of molar mass 60 g mol^{- 1} and 0.9 g of a non-volatile non-electrolyte solute ' B^{’}' of molar mass 180 g mol^{- 1} in 100 mL H_{2} O at 27^{\circ} C . Osmotic pressure of the solution will be [Given: R = 0.082 L atm K^{- 1} mol^{- 1}]$ (1) $0.82 atm$ (2) $2.46 atm$ (3) $1.23 atm$ (4) $1.47 atm$ 362. $Choose the correct statement.$ (1) $K_{H} value is same for a gas in any solution.$ (2) $Higher the K_{H} value more the solubility of gas.$ (3) $K_{H} value increases on increasing the temperature of the solution.$ (4) $none of the above$ 363. $Consider the following aqueous solutions. (I) 2.2 g Glucose in 125 mL of solution. (II) 1.9 g Calcium chloride in 250 mL of solution. (III) 9.0 g Urea in 500 mL of solution. (IV) 20.5 g Aluminium sulphate in 750 mL of solution. The correct increasing order of boiling point of these solutions will be : [Given : Molar mass in gmol^{- 1} : H = 1, C = 12, N = 14, O = 16, Cl = 35.5, Ca = 40, Al = 27 and S = 32]$ (1) $III < I < II < IV$ (2) $I < II < III < IV$ (3) $II < III < I < IV$ (4) $II < III < IV < I$ 364. $1.24 g of AX_{2} (molar mass 124 g mol^{- 1}) is dissolved in 1 kg of water to form a solution with boiling point of 100.0156^{\circ} C, while 25.4 g^{\circ} of AY_{2} (molar mass 250 g mol^{- 1}) in 2 kg of water constitutes a solution with a boiling point of 100.0260^{\circ} C . K_{b} (H_{2} O) = 0.52 K kg mol^{- 1} Which of the following is correct?$ (1) $A X_{2} is fully ionised while A Y_{2} is completely unionised.$ (2) $AX_{2} is completely unionised while AY_{2} is fully ionised.$ (3) $AX_{2} and AY_{2} (both) are completely unionised.$ (4) $AX_{2} and AY_{2} (both) are fully ionised.$ 365. $' g of a non-volatile electrolyte solid solute of molar mass when dissolved in 100 mL water, decreases vapour pressure of water from 640 mm Hg to 600 mm Hg. If aqueous solution of the electrolyte boils at 375 K and for water is , then the mole fraction of the electrolyte solute () in the solution can be expressed as(Given : density of water and boiling point of water )$ (1) $\frac{2 \cdot 6}{16} \times \frac{M}{W}$ (2) $\frac{16}{2 \cdot 6} \times \frac{W}{M}$ (3) $\frac{1.3}{8} \times \frac{M}{W}$ (4) $\frac{1.3}{8} \times \frac{W}{M}$ 366. $For an ideal binary liquid mixture$ (1) $Δ S_{(mix)} = 0; Δ G_{(mix)} = 0$ (2) $Δ H_{(mix)} = 0; Δ S_{(mix)} < 0$ (3) $Δ V_{(mix)} = 0; Δ G_{(mix)} > 0$ (4) $Δ S_{(mix)} > 0; Δ G_{(mix)} < 0$ 367. $Match List-I and List-II. List-I A. Osmosis B. Reverse osmosis C. Electro osmosis D. Electrophoresis List-II I. Solvent molecules pass through semi permeable membrane towards solvent side. II. Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes. III. Solvent molecules pass through semi permeable membrane towards solution side IV. Dispersion medium moves in an electric field. Choose the correct answer from the options given below:$ (1) $A-I,B-III,C-IV,D-II$ (2) $A-III, B-I, C-IV, D-II$ (3) $A-III, B-I, C-II, D-IV$ (4) $A-I, B-III, C-II, D-IV$ 368. $The following solutions were prepared by dissolving 10 g of glucose (C_{6} H_{12} O_{6}) in 250 ml of water (P_{1}), 10 g of urea (CH_{4} N_{2} O) in 250 ml of water (P_{2}) and 10 g of sucrose (C_{12} H_{22} O_{11}) in 250 ml of water (P_{3}) . The right option for the decreasing order of osmotic pressure of these solutions is:$ (1) $P_{1} > P_{2} > P_{3}$ (2) $P_{2} > P_{3} > P_{1}$ (3) $P_{3} > P_{1} > P_{2}$ (4) $P_{2} > P_{1} > P_{3}$ 369. $Isotonic solutions are having the same$ (1) $surface tension$ (2) $vapour pressure$ (3) $osmotic pressure$ (4) $viscosity:$ 370. $Isotonic solutions have same$ (1) $Freezing temperature$ (2) $Osmotic pressure$ (3) $Boiling temperature$ (4) $Vapour pressure$ 371. $Evaluate the following statements for their correctness. (A) The elevation in boiling point temperature of water will be same for 0.1 M NaCl and 0.1 M urea. (B) Azeotropic mixtures boil without change in their composition (C) Osmosis always takes place from hypertonic to hypotonic solution (D)The density of 32% H_{2} S O_{4} solution having molarity 4.09 M is approximately 1.26 g m L^{- 1} (E) A negatively charged sol is obtained when KI solution is added to silver nitrate solution. Choose the correct answer from the options given below;$ (1) $B, D, and E only$ (2) $A, B, and D only$ (3) $A and C only$ (4) $B and D only$ 372. $A sample of water is found to contain 5.85 % (w / W) of AB (molecular mass 58.5) and 9.50 % (w / W) X Y_{2} (molecular mass 95). Assuming 80 % ionisation of AB and 60 % ionisation of X Y_{2}, the freezing point of water sample is [Given: K_{f} for water is 1.86 kkg mol^{- 1} . Freezing point of pure water is 273 K and A, B and Y are monovalent ions.)$ (1) $264.25 K$ (2) $265.56 K$ (3) $280.44 K$ (4) $281.75 K$ 373. $Elements P and Q form two types of non-volatile, non-ionizable compounds PQ and PQ_{2} . When 1 g of PQ is dissolved in 50 g of solvent ' A^{’}, Δ T_{b} was 1.176 K while when 1 g of PQ_{2} is dissolved in 50 g of solvent^{’} A^{’}, Δ T_{b} was 0.689 K . (K_{b} of ' A^{’} = 5 K kg mol^{- 1}). The molar masses of elements P and Q (in gmol^{- 1}) respectively, are:$ (1) $70,110$ (2) $65,145$ (3) $25,60$ (4) $60,25$ 374. $Which one is a colligative property?$ (1) $Boiling point$ (2) $Vapour pressure$ (3) $Osmotic pressure$ (4) $Freezing point$ 375. $Vapour pressure of chloroform (C H C l_{3}) and dichloromethane (C H_{2} C l_{2}) at 2 5^{\circ} C are 200 mm Hg and 41.5 mm Hg respectively. Vapour pressure of the solution obtained by mixing 25.5 g of C H C l_{3} and 40 g of C H_{2} C l_{2} at the same temperature will be (Molecular mass of C H C l_{3} = 119.5 u and molecular mass of C H_{2} C l_{2} = 85 u)$ (1) $173.9 mm Hg$ (2) $615.0 mm Hg$ (3) $347.9 mm Hg$ (4) $None$ 376. $What is the effect of external pressure on the osmotic pressure (OP) of a solution?$ (1) $OP decreases with increase of pressure$ (2) $OP decreases initially, then increases$ (3) $OP remained nearly same with increase/decrease of external pressure$ (4) $OP increases with increase of pressure$ 377. $An aqueous solution of a salt M X_{2} at certain temperature has a van’t Hoff factor of 2. The degree of dissociation for this solution of the salt is :$ (1) $0.67$ (2) $0.33$ (3) $0.80$ (4) $0.50$ 378. $An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams ofglucose are added to the beaker of water, the rate at which water molecules$ (1) $leaves the solution increases$ (2) $leaves the vapour increases$ (3) $leaves the vapour decreases$ (4) $leaves the solution decreases$ 379. $At 35^{\circ} C the vapour pressure of C S_{2} is 512 mmHg and that of acetone is 344 mmHg . A solution of Hg in acetone has a total vapour pressure of 600 mmHg . The false statement amongst the following is:$ (1) $heat must be absorbed in order to produce the solution at 35^{\circ} C$ (2) $Does not obey Raoult’s law$ (3) $a mixture of 100 mLC S^{2} and 100 mL acetone has a volume < 200 mL$ (4) $C S^{2} and acetone are less attracted to each other than to themselves$ 380. $If M, W and V represent molar mass of solute, mass of solute and volume of solution in litres respectively, which among the following equations is true?$ (1) $π = \frac{MWR}{TV}$ (2) $π = \frac{TMR}{WV}$ (3) $π = \frac{TWR}{VM}$ (4) $π = \frac{TRV}{WM}$ 381. $The beans are cooked earlier in pressure cooker because$ (1) $boiling point increases with increasing pressure$ (2) $boiling point decreases with increasing pressure$ (3) $extra pressure of pressure cooker softens the beans$ (4) $internal energy is not lost while cooking in pressure cooker.$ 382. $A binary liquid solution is prepared by mixing n-heptane and ethanol. Which one of the following statement is correct regarding the behaviour of the solution?$ (1) $The solution is non-ideal, showing +ve deviation from Raoult’s Law.$ (2) $The solution in non-ideal, showing -ve deviation from Raoult’s Law.$ (3) $n-heptane shows +ve deviation while ethanol shows -ve deviation from Raoult’s Law.$ (4) $The solution formed is an ideal solution.$ 383. $A substance ' X ' (1.5 g) dissolved in 150 g of a solvent ' Y ' (molar mass = 300 g mol^{- 1}) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent ' Y ' is____\times 10^{- 2} . (nearest integer) [Given : K_{b} of the solvent = 5.0 K kg mol^{- 1}] Assume the solution to be dilute and no association or dissociation of X takes place in solution.$ 384. $Sea water, which can be considered as a 6 molar (6 M) solution of NaCl, has a density of 2 g mL^{- 1} . The concentration of dissolved oxygen (O_{2}) in sea water is 5.8 ppm. Then the concentration of dissolved oxygen (O_{2}) in sea water, is x \times 10^{- 4} m . x = . (Nearest integer) Given: Molar mass of NaCl is 58.5 g mol^{- 1} Molar mass of O_{2} is 32 g mol^{- 1}$ 385. $The osmotic pressure of a living cell is 12 atm at 300 K. The strength of sodium chloride solution that is isotonic with the living cell at this temperature is____gL^{- 1} . (Nearest integer) Given : R = 0.08 L atm K^{- 1} mol^{- 1} Assume complete dissociation of NaCl (Given : Molar mass of Na and Cl are 23 and 35.5 g mol^{- 1} respectively.)$ 386. $Considering acetic acid dissociates in water, its dissociation constant is 6.25 \times 10^{- 5} . If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at - x \times 10^{- 2 \circ} C, provided pure water freezes at 0^{\circ} C . x =______(Nearest integer) Given: (K_{f})_{water} = 1.86 K kg mol^{- 1} . density of acetic acid is 1.2 g mol^{- 1} . molar mass of water = 18 g mol^{- 1} . molar mass of acetic acid = 60 gmol^{- 1} . density of water = 1 g cm^{- 3} Acetic acid dissociates as CH_{3} COOH ⇌ CH_{3} COO^{⊖} + H^{\oplus}$ 387. $Consider the dissociation of the weak acid HX as given below HX (aq) ⇌ H^{+} (aq) + X^{-} (aq), Ka = 1.2 \times 10^{- 5} (K_{a} :) dissociation constant] The osmotic pressure of 0.03 M aqueous solution of HX at 300 K is______\times 10^{- 2} bar (nearest integer). [Given : R = 0.083 Lbarmol^{- 1} K^{- 1}]$ 388. $∆ T_{b} = K_{b} \times m o l a l i t y M=250$ 389. $The number of pairs of the solution having the same value of the osmotic pressure from the following is - (Assume 100% ionization) A. 0.500 M C_{2} H_{5} OH (aq) and 0.25 M KBr (aq) B. 0.100 M K_{4} [Fe (C N)_{6}] (aq) and 0.100 M F e S O_{4} (N H_{4})_{2} S O_{4} (aq) C. 0.05 M K4Fe (C N)_{6}] (aq) and 0.25 M NaCl (aq) D. 0.15 M NaCl (aq) and 0.1 M B a C l_{2} (aq) E. 0.02 M KC1. M g C l_{2} - 6 H_{2} 0 (aq) and 0.05 M KC1 (aq)$ 390. $The plot given below shows P-T curves (where P is the pressure and T is the temperature) for two solvents X and Y and isomolal solutions of NaCl in these solvents. NaCl completely dissociates in both the solvents. On addition of equal number of moles of a non-volatile solute S in equal amount (in kg) of these solvents, the elevation of boiling point of solvent X is three times that of solvent Y. Solute S is known to undergo dimerization in these solvents. If the degree of dimerization is 0.7 in solvent Y, the degree of dimerization in solvent X is ____.$