Solutions PYQs Set 7 (PDF)

Set 7 of 12 · Questions 181-210 of 332

In the print window choose “Save as PDF”. The file prints without a web address or date line.

Mere Teacher · Previous Year Questions NEET Chemistry · Solutions · Set 7 (Q181-210)
Scan or visit mereteacher.com for free PYQ practice, timed CBT tests, step-by-step solutions and BroBot AI. Answers and solutions are free with a sign-up.
181. $What is the molar mass of solute when 5 gram solute dissolved in 70 gram solvent lowers its freezing point by 2.5 K ? (cryoscopic constant for solvent is 4.9 K kg mol^{- 1})$ (1) $100 g mol^{- 1}$ (2) $160 g mol^{- 1}$ (3) $120 g mol^{- 1}$ (4) $140 g mol^{- 1}$ 182. $The vapour pressure of pure benzene and toluene are 160 and respectively. The mole fraction of benzene in vapour phase in contact with equimolar solution of benzene and toluene is$ (1) $0.073$ (2) $0.027$ (3) $0.27$ (4) $0.73$ 183. $If 3 g of glucose (molar mass = 180 g) is dissolved in 60 g of water at 15^{\circ} C, the osmotic pressure of the solution will be$ (1) $6.57 atm$ (2) $5.57 atm$ (3) $0.34 atm$ (4) $0.65 atm .$ 184. $Which of the following substances show the highest colligative properties?$ (1) $0.1 M BaCl_{2}$ (2) $0.1 M AgNO_{3}$ (3) $0.1 M urea$ (4) $0.1 M NH43PO4$ 185. $At T (K), the partial pressure of dissolved oxygen in 1 L water is 1 bar. The concentration of oxygen is ppm is (K_{H} of O_{2} at T (K) is (50 kbar)$ (1) $71.0$ (2) $35.50$ (3) $17.75$ (4) $81.10$ 186. $The vapour pressure of acetone at 20ºC is 185 torr. When 1.2 g of a non-volatile substance was dissolved in 100 g of acetone at 20ºC, its vapour pressure was 183 torr. The molar mass (g m o l^{-1}) of the substance is:$ (1) $32$ (2) $64$ (3) $128$ (4) $488$ 187. $A 5% solution of cane sugar (mol. w t . = 342) is isotonic with 1% solution of a substance X. The molecular weight of X is$ (1) $68.4$ (2) $171.2$ (3) $34.2$ (4) $136.8$ 188. $9 gram anhydrous oxalic acid (mol. wt. = 90) was dissolved in 9.9 moles of water. If vapour pressure of pure water is P_{1}^{o}, the vapour pressure of solution is$ (1) $0.99 P_{1}^{0}$ (2) $0.1 P_{1}^{0}$ (3) $0.90 P_{1}^{o}$ (4) $1.1 P_{1}^{\circ}$ 189. $x g of MgSO_{4} (i = 1.8) is in 2.5 L of solution has an osmotic pressure of 2.463 atm at 27^{\circ} C . What is the value of x in g ?$ (1) $33.2$ (2) $6.6$ (3) $3.3$ (4) $16.6$ 190. $A solution is formed by the combination of two liquids such as dichloromethane and chloroform. The partial pressures of dichloromethane and chloroform in solution are 285.5 and 62.4 mmHg respectively. What is the total pressure of the solution?$ (1) $223.1 mmHg$ (2) $347.9 mmHg$ (3) $357.9 mmHg$ (4) $337.9 mmHg$ 191. $The freezing point depression constant for water is - 1.8 6^{o} C m^{- 1} . If 5.00 g N a_{2} S O_{4} is dissolved in 45.0 g H_{2} O, the freezing point is changed by - 3.8 2^{o} C . Calculate the van’t Hoff factor for N a_{2} S O_{4} .$ (1) $2.05$ (2) $2.63$ (3) $3.11$ (4) $0.381$ 192. $6 g of a non-volatile solute (x) is dissolved in 100 g of water. The relative lowering of vapour pressure of resultant solution is 0.006 . What is the molar mass (in g mol^{- 1}) of x ?$ (1) $60$ (2) $360$ (3) $100$ (4) $180$ 193. $A solution of 1.25 g of P in 50 g of water lowers freezing point by 0.3^{\circ} C . Molar mass of P is 94. K_{f (water)} = 1.86 K kg mol^{- 1} . The degree of association of P in water is$ (1) $80 %$ (2) $60 %$ (3) $65 %$ (4) $75 %$ 194. $What weight of glucose must be dissolved in 100 g of water to lower the vapour pressure by 0.20 mm Hg? (Assume dilute solution is being formed) Given: Vapour pressure of pure water is 54.2 mm Hg at room temperature. Molar mass of glucose is 180 g m o l^{- 1}$ (1) $3.59g$ (2) $3. 69 g$ (3) $4.69g$ (4) $2.59g$ 195. $Which of the following condition is correct for reverse osmosis? (C =) Concentration of solution in mol^{- 1}; T = Temperature in Kelvin scale; n = no of moles of solute]$ (1) $P_{ext} = CRT$ (2) $P_{ext} > CRT$ (3) $P_{ext} < CRT$ (4) $P_{ext} > nRT$ 196. $The freezing point of solution containing 10 mL of nonvolatile and non-electrolyte liquid "A" in 500 g of water is - 0.413^{\circ} C . If K_{f} of water is 1.86 K kg mol^{- 1} and the molecular weight of A = 60 g mol^{- 1}, what is the density of the solution in g mL^{- 1} ? (Assume D_{mix} V = 0)$ (1) $1.13$ (2) $1.3$ (3) $0.90$ (4) $0.993$ 197. $Which one of the following aqueous solutions will exhibit highest boiling point?$ (1) $0.01 M N a_{2} S O_{4}$ (2) $0.01 M K N O_{3}$ (3) $0.015 M urea$ (4) $0.015 M glucose$ 198. $Which one is not correct mathematical equation for Dalton's Law of partial pressure? Here p = total pressure of gaseous mixture$ (1) $, where mole fraction of ith gas in gaseous mixture pressure of ith gas in pure state$ (2) $p = p_{1} + p_{2} + p_{3}$ (3) $p = n_{1} \frac{RT}{V} + n_{2} \frac{RT}{V} + n_{3} \frac{RT}{V}$ (4) $, where partial pressure of ith gas mole fraction of ith gas in gaseous mixture$ 199. $A solution is prepared by dissolving 10 g of a nonvolatile solute (molar mass, ' M' g mol^{- 1}) in 360 g of water. What is the molar mass in g mol^{- 1} of solute if the relative lowering of vapour pressure of solution is 5 \times 10^{- 3} ?$ (1) $199$ (2) $99.5$ (3) $299$ (4) $149.5$ 200. $Two liquids X and Y form an ideal solution. At 300K, vapour pressure of the solution containing 1 mol of X and 3 mol of Y is 550 mmHg. At the same temperature, if 1 mol of Y is further added to this solution, vapour pressure of the solution increases by 10 mmHg. Vapour pressure (in mmHg) of X and Y in their pure states will be, respectively$ (1) $300 and 400$ (2) $400 and 600$ (3) $500 and 600$ (4) $200 and 300$ 201. $Freezing point of a 4% aqueous solution X is equal to freezing point of 12% aqueous solution of Y. if molecular weight of X is A, then molecular weight of Y is:$ (1) $3A$ (2) $2A$ (3) $A$ (4) $4A$ 202. $What is the van't Hoff factor of Ferric Sulphate (Assume 100 % ionization)$ (1) $2$ (2) $4$ (3) $5$ (4) $3$ 203. $At 300 K, the osmotic pressure of a decinormal solution of sodium chloride is 4.82 atm . The degree of dissociation of sodium chloride is x \times 10^{- 2} . The value of x is (R = 0.082 L atm K^{- 1} mol^{- 1})$ (1) $90$ (2) $96$ (3) $93$ (4) $88$ 204. $How many grams of glucose must be added to 0.5 litre of a solution so that its osmotic pressure is same as that of a solution of 9.2 g of glucose dissolved in a litre?$ (1) $1.15$ (2) $9.22$ (3) $2.31$ (4) $4.60$ 205. $The molality of an aqueous dilute solution containing non-volatile solute is 0.1 m . What is the boiling temperature (in^{\circ} C) of solution? (Boiling point elevation constant, K_{b} = 0.52 kg mol^{- 1} K; boiling temperature of water (= 100^{\circ} C)$ (1) $100.0052$ (2) $100.052$ (3) $100.0$ (4) $100.52$ 206. $6 g of a mixture of naphthalene (C_{10} H_{8}) and anthracene (C_{14} H_{10}) is dissolved in 300 gram of benzene. If the depression in freezing point is 0.70 K, the composition of naphthalene and anthracene in the mixture respectively ing are (molal depression constant of benzene is 5.1 K kg (mol^{- 1})$ (1) $2.60, 3.40$ (2) $3.40, 2.60$ (3) $2.90, 3.10$ (4) $3.10, 2.90$ 207. $Given below are two statements: Statement (I): Molal depression constant K_{f} is given by \frac{M _{1} RT _{f}}{Δ S _{fus}}, where symbols have their usual meaning. Statement (II): K_{f} for benzene is less than the K_{f} for water. In the light of the above statements, choose the most appropriate answer from the options given below:$ (1) $Statement I is correct but Statement II is incorrect$ (2) $Both Statement I and Statement II are incorrect$ (3) $Statement I is incorrect but Statement II is correct$ (4) $Both Statement I and Statement II are correct$ 208. $Solubility of gas in a liquid increases with$ (1) $increase of P and decrease of T$ (2) $decrease of P and decrease of T$ (3) $increase of P and increase of T$ (4) $decrease of P and increase of T .$ 209. $The correct option for the value of vapour pressure of a solution at 45^{\circ} C with benzene to octane in molar ratio 3 : 2 is: [At 45^{\circ} C vapour pressure of benzene is 280 mm Hg and that of octane is 420 mm Hg . Assume Ideal gas]$ (1) $168 mm of Hg$ (2) $336 mm of Hg$ (3) $350 mm of Hg$ (4) $160 mm of Hg$ 210. $The vapour pressure of a pure liquid is 70 torr at 300 . It forms an ideal solution with another liquid . The mole fraction of is 0.2 and total vapour pressure of the solution is 84 torr at the same temperature. The vapour pressure of pure liquid (in torr) is$ (1) $140$ (2) $90$ (3) $120$ (4) $80$