Solutions PYQs Set 12 (PDF)

Set 12 of 14 · Questions 331-360 of 419

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Solutions · Set 12 (Q331-360)
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331. $For a dilute solution containing 2.5 g of a non- volatile non- electrolyte solute in 100 g of water, the elevation in boiling point at 1 atm pressure is 2ºC. Assuming concentration of solute is much lower than the concentration of solvent, the vapour pressure (mm of Hg) of the solution is (take K_{b} = 0.76 K kg m o l^{-1})$ (1) $724$ (2) $740$ (3) $736$ (4) $718$ 332. $Which one of the following is incorrect for ideal solution?$ (1) $∆ H_{mi x} = 0$ (2) $∆ U_{mi x} = 0$ (3) $by Raoult’s law = 0$ (4) $∆ G_{mi x} = 0$ 333. $Mixture(s) showing positive deviation from Raoult's law at 35ºC is(are)$ (1) $carbon tetrachloride + methanol$ (2) $carbon disulphide + acetone$ (3) $benzene + toluene$ (4) $phenol + aniline$ 334. $Freezing point of a 4% aqueous solution of X is equal to freezing point of 12% aqueous solution of Y. If molecular weight of X is A, then molecular weight of Y is:$ (1) $4A$ (2) $2A$ (3) $3A$ (4) $A$ 335. $Which one of the following electrolytes has the same value of Van’t Hoff factor (i) as that of A l_{2} (S O_{4})_{3} (if all are 100% ionised)?$ (1) $A l (N O_{3})_{3}$ (2) $K_{4} [Fe (CN)]$ (3) $K_{2} S O_{4}$ (4) $K_{3} [Fe (CN)]$ 336. $At 10 0^{0} C the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If K_{b} = 0.52, the boiling point ofthis solution will be$ (1) $102 C$ (2) $103 C$ (3) $101 C$ (4) $100 C$ 337. $Consider the given plots of vapour pressure (VP) vs temperature(T/K). Which amongst the following options is correct graphical representation showing Δ T_{f}, depression in the freezing point of a solvent in a solution?$ (1) (2) (3) (4) 338. $For a solution formed by mixing liquids L and M, the vapour pressure of L plotted against the mole fraction of M in solution is shown in the following figure. Here and represent mole fractions of L and M, respectively, in the solution. The correct statement(s) applicable to this system is (are)$ (1) $The point Z represents vapour pressure of pure liquid M and Raoult's law is obeyed from x_{L} = 0 to x_{L} = 1.$ (2) $Attractive intermolecular interactions between L-L in pure liquid L and M-M in pure liquid M are stronger than those between L-M when mixed in solution$ (3) $The point Z represents vapour pressure of pure liquid M and Raoult's law is obeyed when xL \to 0$ (4) $The point Z represents vapour pressure of pure liquid L and Raoult's law is obeyed when xL \to 1$ 339. $How many grams of concentrated nitric acid solution should be used to prepare 250 m L of 2.0 M H N O_{3} ? The concentrated acid is 70% H N O_{3} .$ (1) $70.0 g conc. H N O_{3}$ (2) $54.0 g conc. H N O_{3}$ (3) $45.0 g conc. H N O_{3}$ (4) $90.0 g conc. H N O_{3}$ 340. $A 0.004 M solution of N a_{2} S O_{4} is isotonic with 0.010 M solution of glucose at same temperature. The apparent percentage dissociation of N a_{2} S O_{4} is :$ (1) $25%$ (2) $50%$ (3) $75%$ (4) $85%$ 341. $A solution is prepared by mixing 8.5 g of and 11.95 g of . If vapour pressure of and at 298 K are 415 and 200 mmHg respectively, the mole fraction of in vapour form is :(Molar mass of Cl = 35.5 g )$ (1) $0.675$ (2) $0.162$ (3) $0.486$ (4) $0.325$ 342. $Molarity of a 50 mL H_{2} S O_{4} solution is 10.0 M . If the density of the solution is 1.4 g/cc, calculate its molality$ (1) $7.14$ (2) $8.00$ (3) $10.0$ (4) $23.8$ 343. $A solution contains non volatile solute of molecular mass M_{2} . Which of the following can be used to calculate the molecular mass of solute in terms of osmotic pressure?$ (1) $M_{2} = (\frac{m _{2}}{π}) V R T$ (2) $M_{2} = (\frac{m _{2}}{V}) \frac{R T}{π}$ (3) $M_{2} = (\frac{m _{2}}{V}) π R T$ (4) $M_{2} = (\frac{m _{2}}{V}) \frac{π}{R T} (m_{2} = mass of solute, V = volume of solution, π = osmotic pressure)$ 344. $Liquids A and B form an ideal solution in the entire composition range. At 350 K, the vapor pressure of pure A and pure B are 7 \times 10³ Pa and 12 \times 10³ Pa, respectively. The composition of the vapor in equilibrium with a solution containing 40 mole percent of A at this temperature is :$ (1) $x_{A} = 0.37; x_{B} = 0.63$ (2) $x_{A} = 0.28; x_{B} = 0.72$ (3) $x_{A} = 0.4; x_{B} = 0.6$ (4) $x_{A} = 0.76; x_{B} = 0.24$ 345. $A solution of acetone in ethanol$ (1) $obeys Raoult’s law$ (2) $shows a negative deviation from Raoult’s law$ (3) $shows a positive deviation from Raoult’s law$ (4) $behaves like a near ideal solution.$ 346. $Given below are two statements : one is labelled as Assertion (a) and the other is labelled as Reason (R) Assertion (a) : At 10°C, the density of a 5M solution of KC1 [atomic masses of K and Cl are 39 & 35.5 g mol^{- 1} . The solution is cooled to -21°C. The molality of the solution will remain unchanged. Reason (R) : The molality of a solution does not change with temperature as mass remains unaffected with temperature. In the light of the above statements, choose the correct answer from the options given below:$ (1) $Both (a) and (R) are true and (R) is the correct explanation of (a)$ (2) $Both (a) and (R) are true but (R) is not the correct explanation of (a)$ (3) $(a) is true but (R) is false$ (4) $(a) is false but (R) is true$ 347. $150 g of acetic acid was contaminated with 10.2 g ascorbic acid (C_{6} H_{8} 0_{6}) to lower down its freezing point by (x \times 1 0^{- 1})^{0} C. The value of x is________.(Nearest integer) [Given K_{f} = 3.9 K kg m o l^{- 1}; Molar mass of ascorbic acid = 176 g m o l^{- 1}]$ 348. $An artificial cell is made by encapsulating 0.2 M glucose solution within a semipermeable membrane. The osmotic pressure developed when the artificial cell is placed within a 0.05 M solution of NaCl at 300 K is______\times 10^{- 1} bar. (nearest integer). [Given : R = 0.083 Lbarmol^{- 1} K^{- 1}] Assume complete dissociation of NaCl$ 349. $80 mole percent of M g C l_{2} is dissociated in aqueous solution. The vapour pressure of 1. 0 molal aqueous solution of M g C l_{2} at 38°C is_____mm Hg. (Nearest integer) Given: Vapour pressure of water at 38°C is 50 mm Hg$ 350. $The osmotic pressure exerted by a solution prepared by dissolving 2.0 g of protein of molar mass 60 kg m o l^{- 1} in 200 mL of water at 27°C is _______Pa. [integer value] (use R = 0.083 L bar m o l^{- 1} K^{- 1})$ 351. $The osmotic pressure of solutions of PVC in cyclohexanone at 300 K arc plotted on the graph.The molar mass of PVC is___________g m o l^{- 1} (Nearest integer) (Given : R = 0.083 L atm K^{- 1} m o l^{- 1})$ 352. $When ' x' \times 10^{- 2} mL methanol (molar mass = 32 g; density = 0.792 g / cm^{3}) is added to 100 mL water (density = 1 g / cm^{3}), the following diagram is obtained. x =_______ (nearest integer). [Given : Molal freezing point depression constant of water at 273.15 K is 1.86 K kg mol^{- 1}]$ 353. $2g of a non-volatile non-electrolyte solute is dissolved in 200 g of two different solvents A and B whose ebullioscopic constants are in the ratio of 1:8. The elevation in boiling points of A and B are in the ratio \frac{x}{y} (x : y). The value of y is_________(Nearest integer)$ 354. $Sea water contains 29.25% NaCl and 19% M g C l_{2} by weight of solution. The normal boiling point of the sea water is °C (Nearest integer) Assume 100% ionization for both NaCl and M g C l_{2} Given: K_{b} (H_{2} O = 0.52 K kg m o l^{- 1}) Molar mass of NaCl and M g C l_{2} is 58. 5 and 95 g m o l^{- 1} respectively$ 355. $Mass of Urea (N H_{2} C O N H_{2}) required to be dissolved in 1000 g of water in order to reduce the vapour pressure of water by 25% is_______g. (Nearest integer) Given : Molar mass of N, C, O and H are 14, 12, 16 and 1 g m o l^{- 1} respectively.$ 356. $C_{6} H_{6} freezes at 5.5 °C. The temperature at which a solution of 10 g of C_{4} H_{10} in 200 g of C_{6} H_{6} freeze is ____ °C. (The molal freezing point depression constant of C_{6} H_{6} is 5.12 °C/m)$ 357. $2.5 g of a non-volatile, non-electrolyte is dissolved in 100 g of water at 25^{\circ} C . The solution showed a boiling point elevation by 2^{\circ} C . Assuming the solute concentration is negligible with respect to the solvent concentration, the vapor pressure of the resulting aqueous solution is mm of Hg (nearest integer) [Given : Molal boiling point elevation constant of water (K_{b}) = 0.52 K . kgmol^{- 1}, 1 atm pressure = 760 mm of Hg, molar mass of water (= 18 g mol^{- 1})$ 358. $A soft drink was bottled with a partial pressure of CO_{2} of 3 bar over the liquid at room temperature. The partial pressure of CO_{2} over the solution approaches a value of 30 bar when 44 g of CO_{2} is dissolved in 1 kg of water at room temperature. The approximate pH of the soft drink is \times 10^{- 1} (First dissociation constant of H_{2} CO_{3} = 4.0 \times 10^{- 7}; log 2 = 0.3 density of the soft drink = 1 gmL^{- 1})$ 359. $A solution containing 10 g of an electrolyte AB_{2} in 100 g of water boils at 100.52^{\circ} C . The degree of ionization of the electrolyte (α) is_____\times 10^{- 1} . (nearest integer) [Given : Molar mass of AB_{2} = 200 g mol^{- 1}, K_{b} (molal boiling point elevation const. of water) = 0.52 K kg mol^{- 1}, boiling point of water = 100^{\circ} C; AB_{2} ionises as (AB_{2} \to A^{2 +} + 2 B^{-})$ 360. $2.7 kg of each of water and acetic acid are mixed. The freezing point of the solution will be - x^{\circ} C . Consider the acetic acid does not dimerise in water, nor dissociates in water. x =_______(nearest integer) [Given: Molar mass of water = 18 g mol^{- 1}, acetic acid = 60 g mol^{- 1} K_{f} H_{2} O : 1.86 K kg mol^{- 1} K_{f} acetic acid: 3.90 K kg mol^{- 1} freezing point: H_{2} O = 273 K, acetic acid (= 290 K)$