Solutions PYQs Set 9 (PDF)

Set 9 of 14 · Questions 241-270 of 419

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Solutions · Set 9 (Q241-270)
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241. $The correct option for the value of vapour pressure of a solution at 45^{\circ} C with benzene to octane in molar ratio 3 : 2 is: [At 45^{\circ} C vapour pressure of benzene is 280 mm Hg and that of octane is 420 mm Hg . Assume Ideal gas]$ (1) $168 mm of Hg$ (2) $336 mm of Hg$ (3) $350 mm of Hg$ (4) $160 mm of Hg$ 242. $The vapour pressure of a pure liquid is 70 torr at 300 . It forms an ideal solution with another liquid . The mole fraction of is 0.2 and total vapour pressure of the solution is 84 torr at the same temperature. The vapour pressure of pure liquid (in torr) is$ (1) $140$ (2) $90$ (3) $120$ (4) $80$ 243. $A solution of non-volatile solute is obtained by dissolving 15 g in 200 mL water has depression in freezing point 0.75 K . Calculate the molar mass of solute if cryoscopic constant of water is 1.86 K kg mol^{- 1} .$ (1) $160 g mol^{- 1}$ (2) $186 g mol^{- 1}$ (3) $172 g mol^{- 1}$ (4) $198 g mol^{- 1}$ 244. $From the colligative properties of solution, which one is the best method for the determination of molecular weight of proteins and polymers?$ (1) $Osmotic pressure$ (2) $Lowering in vapour pressure$ (3) $Lowering in freezing point$ (4) $Elevation in boiling point$ 245. $When an electrolyte is dissociated in solution, the van't Hoff factor (i) is$ (1) $> 1$ (2) $< 1$ (3) $= 0$ (4) $= 1$ 246. $Osmotic pressure observed when benzoic acid is dissolved in benzene is less than that expected from theoretical considerations. This is because$ (1) $benzoic acid is an organic solute$ (2) $benzoic acid has higher molar mass than benzene$ (3) $benzoic acid gets associated in benzene$ (4) $benzoic acid gets dissociated in benzene.$ 247. $For an ideal solution, the correct option is:$ (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) $Δ_{mix} G = 0 at constant T and P$ 248. $The solubility of N_{2} in water at 300 K and 500 torr partial pressure is 0.01 g L^{-1} . The solubility (in g L^{-1}) at 750 torr partial pressure is :$ (1) $0.02$ (2) $0.015$ (3) $0.0075$ (4) $0.005$ 249. $Assume a living cell with of glucose solution (aqueous). This cell is immersed inanother solution having equal mole fraction of glucose and water. (Consider the data upto first decimal place only) The cell will:$ (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) $None of these$ 250. $The elevation in boiling point of a solution of 13.44 g of C u C l_{2} in 1kg of water using the following information, will be (Molecular weight of C u C l_{2} = 134.4 and K_{b} = 0.52 K m o l a l^{-1}):$ (1) $0.16$ (2) $0.05$ (3) $0.1$ (4) $0.2$ 251. $What is the freezing point depression constant of a solvent, 50 g of which contain 1 g non volatile solute (molar mass 256 g mol^{- 1}) and the decrease in freezing point is 0.40 K ?$ (1) $3.72 K kg mol^{- 1}$ (2) $1.86 K kg mol^{- 1}$ (3) $4.43 K kg mol^{- 1}$ (4) $5.12 K kg mol^{- 1}$ 252. $H A (aq) ⇌ H^{+} (aq) + A^{-} (aq) The freezing point depression of a 0.1 m aqueous solution of a monobasic weak acid HA is 0.20^{\circ} C . The dissociation constant for the acid is Given: K_{f} (H_{2} O) = 1.8 K kg mol^{- 1}, molality \equiv molarity$ (1) $1.90 \times 10^{- 3}$ (2) $1.38 \times 10^{- 3}$ (3) $1.1 \times 10^{- 2}$ (4) $1.89 \times 10^{- 1}$ 253. $. 6 g of a non-volatile, non-electrolyte X dissolved in 100 g of water freezes at - 0.93^{\circ} C . The molar mass of X in g mol^{- 1} is (K_{f}) of (H_{2} O = 1.86 K kg mol^{- 1})$ (1) $60$ (2) $140$ (3) $180$ (4) $120$ 254. $At 298 K, the vapour pressure of pure water is 25 torr. The vapour pressure of water, when 12 g of urea (molar mass, 60 g mol^{- 1}) and 36 g of glucose (molar mass, 180 g mol^{- 1}) is dissolved in 100 gof water at the same temperature (in torr) is$ (1) $25.02$ (2) $24.12$ (3) $23.92$ (4) $23.32$ 255. $A solution is prepared by dissolving 0.6 g of urea (molar mass = 60 g mol^{- 1}) and 1.8 g glucose (molar mass = 180 g mol^{- 1}) in 100 mL, of water at 27°C. The osmotic pressure of the solution is: (R = 0.08206 L atm K^{- 1} mol^{- 1})$ (1) $8.2 atm$ (2) $2.46 atm$ (3) $4.92 atm$ (4) $1.64 atm$ 256. $The freezing point depression of 0.001 M of A_{x} B_{y} (Fe (CN)_{6}) is 5.58 \times 10^{- 3} K . If the oxidation state of Fe is +2 and K_{f} = 1.86 kg mol^{- 1}, then the total number of possibilities for different types of A and B cations are$ (1) $1$ (2) $2$ (3) $3$ (4) $4$ 257. $The mass of a non-volatile, non-electrolyte solute (molar mass = 50 g m o l^{-1}) needed to be dissolved in 114 g octane to reduce its vapour pressure to 75 %, is :$ (1) $37.5 g$ (2) $75 g$ (3) $150 g$ (4) $none$ 258. $The vapour pressures of pre liquids A and B are 400 and 600 mmHg, respectively at 298 K. On mixing the two liquids, the sum of their initial volumes is equal to the volume of the final mixture. The mole fraction of liquid B is 0.5 in the mixture. The vapour pressure of the final solution, the mole fraction of components A and B in vapour phase, respectively are-$ (1) $450 mmHg, 0.4, 0.6$ (2) $500 mmHg, 0.5, 0.5$ (3) $450mmHg, 0.5, 0.5$ (4) $500 mmHg, 0.4, 0.6$ 259. $Henry's law is valid for(A) Ammonia gas dissolution in water(B) O2 gas dissolution in unsaturated blooc(C) O2 dissolution in water(D) CO_{2} dissolution in water$ (1) $A and B$ (2) $B and C$ (3) $C and D$ (4) $B and D$ 260. $The osmotic pressure of a dilute solution of an ionic compound XY in water is four times that of a solution of 0.01M BaCl_{2} in water. Assuming complete dissociation of the given ionic compounds in water, the concentration of XY (in mol L^{- 1}) in solution is :$ (1) $4 \times 10^{- 2}$ (2) $6 \times 10^{- 2}$ (3) $4 \times 10^{- 4}$ (4) $16 \times 10^{- 4}$ 261. $The van't Hoff factor ' i' accounts for$ (1) $extent of dissolution of solute$ (2) $extent of dissociation of solute$ (3) $extent of mobility of solute$ (4) $extent of solubility of solute.$ 262. $20% of acetic acid is dissociated when its 5 g is added to 500 mL of water. The depression in freezing point of such water is_______x 1 0^{- 3} °C. Atomic mass of C, H and O are 12, 1 and 16 a.m.u. respectively. [Given : Molal depression constant and density of water are 1.86 K kg m o l^{- 1} and 1 g c m^{- 3} respectively.$ 263. $If A_{2} B is 30 % ionised in an aqueous solution, then the value of van't Hoff factor (i) is_____\times 10^{- 1} .$ 264. $At 363 K, the vapour pressure of A is 21 kPa and that of B is 18 kPa . . One mole of A and 2 moles of B aremixed. Assuming that this solution is ideal, the vapour pressure of the mixture is______kPa . (Round of to theNearest Integer).$ 265. $A 300 mL bottle of soft drink has 0.2 M C O_{2} dissolved in it. Assuming C O_{2} behaves as an ideal gas, the volume of the dissolved C O_{2} at STP is _________mL. (Nearest integer)Given: At STP, molar volume of an ideal gas is 22. 7 L m o l^{- l}$ 266. $If 250 cm^{3} of an aqueous solution containing 0.73 g of a protein A is isotonic with one liter of another aqueous solution containing 1.65 g of a protein B, at 298 K, the ratio of the molecular masses of A and B is \times 10^{- 2} (to the nearest integer).$ 267. $At 300 K, the vapour pressure of a solution containing 1 mole of n -hexane and 3 moles of n -heptane is 550 mm of Hg . At the same temperature, if one more mole of n -heptane is added to this solution, the vapour pressure of the solution increases by 10 mm of Hg . What is the vapour pressure in mm Hg of n -heptane in its pure state$ 268. $The osmotic pressure of a solution of NaCl is 0.10 atm and that of a glucose solution is 0.20 atm . The osmotic pressure of a solution formed by mixing 1 L of the sodium chloride solution with 2 L of the glucose solution is x \times 10^{- 3} atm . x is. (nearest integer)$ 269. $The vapour pressure of pure benzene and methyl benzene at is given as 80 Torr and 24 Torr, respectively. The mole fraction of methyl benzene in vapour phase, in equilibrium with an equimolar mixture of those two liquids (ideal solution) at the same temperature is_____ (nearest integer)$ 270. $Two liquids A and B form an ideal solution. At 320 K, the vapour pressure of the solution, containing 3 mol of A and 1 mol of B is 500 mm Hg. At the same temperature, if 1 mol of A is further added to this solution, vapour pressure of the solution increases by 20 mm Hg. Vapour pressure (in mm Hg) of B in pure state is____. (Nearest integer)$