Solutions PYQs Set 8 (PDF)

Set 8 of 12 · Questions 211-240 of 332

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Mere Teacher · Previous Year Questions NEET Chemistry · Solutions · Set 8 (Q211-240)
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211. $A solution of non-volatile solute is obtained by dissolving 15 g in 200 mL water has depression in freezing point 0.75 K . Calculate the molar mass of solute if cryoscopic constant of water is 1.86 K kg mol^{- 1} .$ (1) $160 g mol^{- 1}$ (2) $186 g mol^{- 1}$ (3) $172 g mol^{- 1}$ (4) $198 g mol^{- 1}$ 212. $From the colligative properties of solution, which one is the best method for the determination of molecular weight of proteins and polymers?$ (1) $Osmotic pressure$ (2) $Lowering in vapour pressure$ (3) $Lowering in freezing point$ (4) $Elevation in boiling point$ 213. $When an electrolyte is dissociated in solution, the van't Hoff factor (i) is$ (1) $> 1$ (2) $< 1$ (3) $= 0$ (4) $= 1$ 214. $Osmotic pressure observed when benzoic acid is dissolved in benzene is less than that expected from theoretical considerations. This is because$ (1) $benzoic acid is an organic solute$ (2) $benzoic acid has higher molar mass than benzene$ (3) $benzoic acid gets associated in benzene$ (4) $benzoic acid gets dissociated in benzene.$ 215. $For an ideal solution, the correct option is:$ (1) $Δ_{mix} S = 0 at constant T and P$ (2) $Δ_{mix} V \neq = 0 at constant T and P$ (3) $Δ_{mix} H = 0 at constant T and P$ (4) $Δ_{mix} G = 0 at constant T and P$ 216. $The solubility of N_{2} in water at 300 K and 500 torr partial pressure is 0.01 g L^{-1} . The solubility (in g L^{-1}) at 750 torr partial pressure is :$ (1) $0.02$ (2) $0.015$ (3) $0.0075$ (4) $0.005$ 217. $Assume a living cell with of glucose solution (aqueous). This cell is immersed inanother solution having equal mole fraction of glucose and water. (Consider the data upto first decimal place only) The cell will:$ (1) $show no change in volume since solution is 0.9 % (ω / ω)$ (2) $shrink since solution is 0.5 % (ω / ω)$ (3) $swell up since solution is 1 % (ω / ω)$ (4) $None of these$ 218. $The elevation in boiling point of a solution of 13.44 g of C u C l_{2} in 1kg of water using the following information, will be (Molecular weight of C u C l_{2} = 134.4 and K_{b} = 0.52 K m o l a l^{-1}):$ (1) $0.16$ (2) $0.05$ (3) $0.1$ (4) $0.2$ 219. $What is the freezing point depression constant of a solvent, 50 g of which contain 1 g non volatile solute (molar mass 256 g mol^{- 1}) and the decrease in freezing point is 0.40 K ?$ (1) $3.72 K kg mol^{- 1}$ (2) $1.86 K kg mol^{- 1}$ (3) $4.43 K kg mol^{- 1}$ (4) $5.12 K kg mol^{- 1}$ 220. $H A (aq) ⇌ H^{+} (aq) + A^{-} (aq) The freezing point depression of a 0.1 m aqueous solution of a monobasic weak acid HA is 0.20^{\circ} C . The dissociation constant for the acid is Given: K_{f} (H_{2} O) = 1.8 K kg mol^{- 1}, molality \equiv molarity$ (1) $1.90 \times 10^{- 3}$ (2) $1.38 \times 10^{- 3}$ (3) $1.1 \times 10^{- 2}$ (4) $1.89 \times 10^{- 1}$ 221. $. 6 g of a non-volatile, non-electrolyte X dissolved in 100 g of water freezes at - 0.93^{\circ} C . The molar mass of X in g mol^{- 1} is (K_{f}) of (H_{2} O = 1.86 K kg mol^{- 1})$ (1) $60$ (2) $140$ (3) $180$ (4) $120$ 222. $At 298 K, the vapour pressure of pure water is 25 torr. The vapour pressure of water, when 12 g of urea (molar mass, 60 g mol^{- 1}) and 36 g of glucose (molar mass, 180 g mol^{- 1}) is dissolved in 100 gof water at the same temperature (in torr) is$ (1) $25.02$ (2) $24.12$ (3) $23.92$ (4) $23.32$ 223. $A solution is prepared by dissolving 0.6 g of urea (molar mass = 60 g mol^{- 1}) and 1.8 g glucose (molar mass = 180 g mol^{- 1}) in 100 mL, of water at 27°C. The osmotic pressure of the solution is: (R = 0.08206 L atm K^{- 1} mol^{- 1})$ (1) $8.2 atm$ (2) $2.46 atm$ (3) $4.92 atm$ (4) $1.64 atm$ 224. $The freezing point depression of 0.001 M of A_{x} B_{y} (Fe (CN)_{6}) is 5.58 \times 10^{- 3} K . If the oxidation state of Fe is +2 and K_{f} = 1.86 kg mol^{- 1}, then the total number of possibilities for different types of A and B cations are$ (1) $1$ (2) $2$ (3) $3$ (4) $4$ 225. $The mass of a non-volatile, non-electrolyte solute (molar mass = 50 g m o l^{-1}) needed to be dissolved in 114 g octane to reduce its vapour pressure to 75 %, is :$ (1) $37.5 g$ (2) $75 g$ (3) $150 g$ (4) $none$ 226. $The vapour pressures of pre liquids A and B are 400 and 600 mmHg, respectively at 298 K. On mixing the two liquids, the sum of their initial volumes is equal to the volume of the final mixture. The mole fraction of liquid B is 0.5 in the mixture. The vapour pressure of the final solution, the mole fraction of components A and B in vapour phase, respectively are-$ (1) $450 mmHg, 0.4, 0.6$ (2) $500 mmHg, 0.5, 0.5$ (3) $450mmHg, 0.5, 0.5$ (4) $500 mmHg, 0.4, 0.6$ 227. $Henry's law is valid for(A) Ammonia gas dissolution in water(B) O2 gas dissolution in unsaturated blooc(C) O2 dissolution in water(D) CO_{2} dissolution in water$ (1) $A and B$ (2) $B and C$ (3) $C and D$ (4) $B and D$ 228. $The osmotic pressure of a dilute solution of an ionic compound XY in water is four times that of a solution of 0.01M BaCl_{2} in water. Assuming complete dissociation of the given ionic compounds in water, the concentration of XY (in mol L^{- 1}) in solution is :$ (1) $4 \times 10^{- 2}$ (2) $6 \times 10^{- 2}$ (3) $4 \times 10^{- 4}$ (4) $16 \times 10^{- 4}$ 229. $The van't Hoff factor ' i' accounts for$ (1) $extent of dissolution of solute$ (2) $extent of dissociation of solute$ (3) $extent of mobility of solute$ (4) $extent of solubility of solute.$ 230. $A solution at 20ºC is composed of 1.5 mol of benzene and 3.5 mol of toluene. If the vapour pressure of pure benzene and pure toluene at this temperature are 74.7 torr and 22.3 torr, respectively, then the total vapour pressure of the solution and the benzene mole fraction in equilibrium with it will be, respectively$ (1) $35.0 torr and 0.480$ (2) $30.5 torr and 0.389$ (3) $38.0 torr and 0.589$ (4) $35.8 torr and 0.280$ 231. $At 0^{\circ} C urea solution has an osmotic pressure if 400 mm . On dilution by x times, its osmotic pressure decreased to 100 mm at 20^{\circ} C . The dilution factor x is approximately$ (1) $4.3$ (2) $2$ (3) $5$ (4) $6.8$ 232. $Which of the following solutions will exhibit highest boiling point?$ (1) $0.01 M Na_{2} SO_{4 (aq)}$ (2) $0.01 M KNO_{3 (aq)}$ (3) $0.015M urea (aq)$ (4) $0.015M glucose e_{(aq)}$ 233. $A 5.25% solution of a substance is isotonic with a 1.5% solution of urea (molar mass = 60g m o l^{-1}) in the same solvent. If the densities of both the solutions are assumed to be equal to 1.0 g c m^{-3}, molar mass of the substance will be$ (1) $105.0 g m o l^{-1}$ (2) $210.0 g m o l^{-1}$ (3) $90.0 g m o l^{-1}$ (4) $15.0 g m o l^{-1}$ 234. $The vapour pressures of two liquids and in their pure states are in ratio of . binary solution of and contains and in the mole proportion of . The mole fraction of in the vapour phase of the solution will be$ (1) $0.33$ (2) $0.2$ (3) $0.25$ (4) $0.52$ 235. $Which among the following is not colligative property?$ (1) $Vapour pressure lowering$ (2) $Boiling point$ (3) $Freezing point depression$ (4) $Osmotic pressure$ 236. $To 500 c m^{3} of water, 3.0 \times 1 0^{-3} kg of acetic acid is added. If 23% of acetic acid is dissociated, what will be the depression in freezing point? k_{f} and density of water are 1.86 K k g m o l e^{-1} and 0.997 g c m^{-3} respectively$ (1) $0.186 K$ (2) $0.228 K$ (3) $0.372 K$ (4) $0.556 K$ 237. $0.2 M aqueous solution of glucose has osmotic pressure 4.9 atm at 300 K . What is the concentration of glucose if it has osmotic pressure 1.5 atm at same temperature?$ (1) $0.03 M$ (2) $0.04 M$ (3) $0.05 M$ (4) $0.06 M$ 238. $Which condition is not satisfied by an ideal solution?$ (1) $∆_{mi x} V = 0$ (2) $∆_{mi x} S = 0$ (3) $Obeyance to Raoult’s Law$ (4) $∆_{mi x} H = 0$ 239. $Commercially available H_{2} SO_{4} is 98 g by weight of H_{2} SO_{4} and 2 g by weight of water. It's density is 1.38 g cm^{- 3} . Calculate the molality (m) of H_{2} SO_{4} (molar mass of H_{2} SO_{4} is 98 g mol^{- 1})$ (1) $500 m$ (2) $20 molal$ (3) $50 m$ (4) $200 m$ 240. $Molecules of benzoic acid (C_{6} H_{5} COOH) dimerise in benzene. ‘w’ g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2 K. If the percentage association of the acid to form dimer in the solution is 80, then w is :(Given that K_{f} = 5 kg m o l^{-1}, Molar mass of benzoic acid = 122 g m o l^{-1})$ (1) $2.4 g$ (2) $1.8 g$ (3) $1.0 g$ (4) $1.5 g$