Solutions PYQs Set 6 (PDF)

Set 6 of 14 · Questions 151-180 of 419

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Solutions · Set 6 (Q151-180)
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151. $Two solutions of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5 M first solution + 520 mL of 1.2 M second solution. What is the molarity of the final mixture ?$ (1) $1.20 M$ (2) $1.50 M$ (3) $1.344 M$ (4) $2.70 M$ 152. $What is the osmotic pressure (in atm) of 0.02 M aqueous glucose solution at 300 K ? (R = 0.082 L atm mol^{- 1} K^{- 1})$ (1) $\frac{1}{0.492}$ (2) $0.492$ (3) $0.988$ (4) $\frac{1}{0.988}$ 153. $At an ideal solution is formed by mixing of toluene with benzene. If the vapour pressure of pure toluene and benzene at are 32 and respectively, the mole fraction of toluene in vapour phase is$ (1) $0.196$ (2) $0.588$ (3) $0.294$ (4) $0.444$ 154. $The solubility product of Cr (OH)_{3} at 298 K is 6.0 \times 10^{- 31} . The concentration of hydroxide ions in a saturated solution of Cr (OH)_{3} will be:$ (1) $(2.22 \times 10^{- 31})^{1/4}$ (2) $(18 \times 10^{- 31})^{1/2}$ (3) $(4.86 \times 10^{- 29})^{1/4}$ (4) $(18 \times 10^{- 31})^{1/4}$ 155. $K_{2} Hg I_{4} is 40% ionized in aqueous solution. The value of its van’t Hoff factor (i) is:$ (1) $1.6$ (2) $1.8$ (3) $2.0$ (4) $2.2$ 156. $The solution from the following with highest depression in freezing point/lowest freezing point is$ (1) $180 g of acetic acid dissolved in water$ (2) $180 g of acetic acid dissolved in benzene$ (3) $180 g of benzoic acid dissolved in benzene$ (4) $180 g of glucose dissolved in water$ 157. $What is Henry's law constant of a gas if solubility of gas in water at 25^{\circ} C is 0.028 mol dm^{- 3} ? [partial pressure of gas = 0.346 bar]$ (1) $0.081 mol dm^{- 3} bar^{- 1}$ (2) $0.075 mol dm^{- 3} bar^{- 1}$ (3) $0.093 mol dm^{- 3} bar^{- 1}$ (4) $0.049 mol dm^{- 3} bar^{- 1}$ 158. $Match List I with List IL List I A. van’t Hoff factor B. k_{f} C. Solutions with same osmotic pressure D. Azeotropes List II I. Cryoscopic constant II. Isotonic solutions III. \frac{N or ma l m o l a r ma ss}{A bn or ma l m o l a r ma ss} IV. Solutions with same composition of vapour above it Choose the correct answer from the options given below:$ (1) $A-III, B-I, C-II, D-IV$ (2) $A-III, B-II, C-I, D-IV$ (3) $A-III, B-I, C-IV, D-II$ (4) $A-I, B-III, C-II, D-IV$ 159. $The molality of solution containing 15.20 g of urea, (molar mass = 60) dissolved in 150 g of water is$ (1) $1.689 mol kg^{- 1}$ (2) $0.5922 mol kg^{- 1}$ (3) $0.1689 mol kg^{- 1}$ (4) $0.2533 mol kg^{- 1}$ 160. $Molal depression constant for a solvent is 4.0 K kg mol^{- 1} . The depression in the freezing point of the solvent for 0.03 mol kg^{- 1} solution of K_{2} SO_{4} is : (Assume complete dissociation of the electrolyte)$ (1) $0.18 K$ (2) $0.24 K$ (3) $0.12 K$ (4) $0.36 K$ 161. $An aqueous solution of a non-volatile solute boils at 100.17^{\circ} C . The temperature at which this solution will freeze (in^{\circ} C) is (K_{b} (H_{2} O) = 0.512^{\circ} Ckg mol^{- 1}, K_{f} (H_{2} O) = 1.86^{\circ} Ckg mol^{- 1})$ (1) $-0.62$ (2) $-0.512$ (3) $-1.24$ (4) $-1.86$ 162. $Molal depression constant (K_{f}) is dependent on$ (1) $Nature of solvent$ (2) $Nature of solute$ (3) $Number of moles of solvent$ (4) $Number of moles of solute$ 163. $0.06 % (w / v) aqueous solution of urea is isotonic with$ (1) $0.6 % glucose solution$ (2) $0.1 M glucose solution$ (3) $0.06 % glucose solution$ (4) $0.01 M glucose solution.$ 164. $The K_{HI} value (kbar) of argon (I), carbon dioxide (II), formaldehyde (III) and methane (IV) are respectively 40.3, 1.67, 1.83 \times 10^{- 5} and 0.413 at 298 K . The increasing order of solubility of gas in liquid is$ (1) $I < II < IV < III$ (2) $III < IV < II < I$ (3) $I < III < II < IV$ (4) $I < IV < II < III$ 165. $At of aqueous solution is mixed with 100 g of aqueous solution. What is the mole fraction of in the resultant solution?(Given: Atomic mass ).(Assume that temperature after mixing remains constant)$ (1) $0.663$ (2) $0.9$ (3) $0.337$ (4) $0.1$ 166. $A solution of sucrose (molar mass = 342 g m o l^{- 1}) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water. The freezing point of the solution obtained will be (K_{f} for water = 1.86 K k g m o l^{- 1})$ (1) $- 0.372 C$ (2) $- 0.520 C$ (3) $+ 0.372 C$ (4) $- 0.570 C$ 167. $A gas ' ' is dissolved in water at 2 bar pressure. Its mole fraction is 0.02 in solution. The mole fraction of water when the pressure of gas is doubled at the same temperature is$ (1) $0.04$ (2) $0.98$ (3) $0.96$ (4) $0.02$ 168. $x % (w / v) solution of urea is isotonic with 4 % (w / v) solution of a non-volatile solute of molar mass 120 g mol^{- 1} . The value of x is$ (1) $2$ (2) $4$ (3) $3$ (4) $5$ 169. $Consider a binary solution of two volatile liquid components 1 and 2. and are themole fractions of component 1 in liquid and vapour phase, respectively. The slope and intercept of the linear plot of are given respectively as:$ (1) $\frac{P _{2}^{0}}{P _{1}^{0}}, \frac{P _{2}^{0} - P _{1}^{0}}{P _{2}^{0}}$ (2) $\frac{P _{1}^{0}}{P _{2}^{0}}, \frac{P _{2}^{0} - P _{1}^{0}}{P _{2}^{0}}$ (3) $\frac{P _{1}^{0}}{P _{2}^{0}}, \frac{P _{1}^{0} - P _{2}^{0}}{P _{2}^{0}}$ (4) $\frac{P _{2}^{0}}{P _{1}^{0}}, \frac{P _{1}^{0} - P _{2}^{0}}{P _{2}^{0}}$ 170. $Which of the following graph correctly represents the plots of K_{H} at 1 bar for gases in water versus temperature?$ (1) (2) (3) (4) 171. $The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol) of the aqueous solution is:$ (1) $13.88\times 1 0^{- 2}$ (2) $13.88\times 1 0^{- 1}$ (3) $13.88$ (4) $13.88\times 1 0^{- 3}$ 172. $The freezing point of an aqueous solution containing 25 g of ethanol in 1000 g of H_{2} O is (K_{f} = 1.86 K kg mol^{- 1})$ (1) $0.25^{\circ} C$ (2) $0.5^{\circ} C$ (3) $- 1.5^{\circ} C$ (4) $- 1^{\circ} C$ 173. $3 g of urea is dissolved in 45 g of H_{2} O . The relative lowering in vapour pressure is$ (1) $0.05$ (2) $0.04$ (3) $0.02$ (4) $0.01$ 174. $Calculate the quantity of CO_{2} required to prepare 1 L of soda water when the soda water was packed under 2 atm of CO_{2} . [Henry's law constant for CO_{2} is 1.67 \times 10^{8} Pa]$ (1) $5.98 g$ (2) $1.21 g$ (3) $2.9 g$ (4) $67.1 g$ 175. $5 g of N a_{2} S O_{4} are was dissolved in x g of H_{2} O. The change in freezing point was found to be 3.82ºC. If N a_{2} S O_{4} is 81.5% ionised, the value of x (K_{f} for water = 1.86ºC kg m o l^{-1}) is approximately :(molar mass of S = 32 g m o l^{-1} and that of Na = 23 g m o l^{-1})$ (1) $45 g$ (2) $65 g$ (3) $25 g$ (4) $15 g$ 176. $van't Hoff factor of centimolal solution of K_{3} (Fe (CN)_{6}) is 3.333. Calculate the percent dissociation of K_{3} (Fe (CN)_{6}) .$ (1) $33.33$ (2) $0.78$ (3) $78$ (4) $23.33$ 177. $What is the depression of freezing point, when mole fraction of non-electrolyte solute in aqueous solution is 0.01 ? of$ (1) $1.246 K$ (2) $1.380 K$ (3) $1.528 K$ (4) $1.043 K$ 178. $1.80 g of solute A was dissolved in 62.5 c m^{3} of ethanol and freezing point of the solution was found to be 155.1 K. The molar mass of solute A is _______g m o l^{- 1} . [Given: Freezing point of ethanol is 156.0 K. Density of ethanol is 0.80 g c m^{- 3} . Freezing point depression constant of ethanol is 2. 00 K k g m o l^{- 1}]$ 179. $Liquids A and B form ideal solution over the entire range of composition. At temperature T, equimolar binary solution of liquids A and B has vapour pressure 45 Torr. At the same temperature, a new solution of A and B having mole fractions and , respectively, has vapour pressure of 22.5 Torr. The value of / in the new solution is ____. (given that the vapour pressure of pure liquid Α is 20 Torr at temperature T)$ 180. $1molal aqueous solution of an electrolyte A_{2} B_{2} is 60% ionised. The boiling point of the solution at 1 atm is_____ K. (Rounded-off to the nearest integer) [Given K_{b} for (H_{2} O) = 0.52 K kg mol^{- 1}]$