Solutions practice · Mixed difficulty

Option B (Carbon disulphide-acetone) is correct because the intermolecular forces between CS2 and acetone are weaker than the forces within each pure liquid, leading to positive deviation.

Option A is correct. The percentage dissociation is calculated using the vapor pressure lowering and Raoult's law, accounting for the van't Hoff factor.

Option A (300) is correct because it is derived from Raoult's Law by setting up and solving a system of equations based on the given vapor pressures.

Option B (0.96 and 1.28 atm) is correct. The degree of association is calculated using the Van't Hoff factor, and osmotic pressure is calculated using $\pi = iCRT$.

Option D ($150 {~g}$) is correct because it is calculated using Raoult's law for vapor pressure lowering, considering the mole fraction of the solute.

Option D is correct because both the Assertion and the Reason are false. Aniline and acetone show negative deviation, and the interaction between them is stronger.

Option B (0.004) is correct because it calculates the mole fraction of the solute using the elevation in boiling point and the ebullioscopic constant.

Option B (40) is correct because it is the molar mass calculated using Raoult's Law and the given weight losses.

Option D (9.32 eV, 8.29 eV) is correct because Beryllium (Be) has a higher ionization potential than Boron (B) due to its stable, fully-filled 2s orbital configuration.

Option A (If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion) is correct because isotonic solutions have the same osmotic pressure, which prevents net osmosis.

Option B (34.2) is correct because it is the mass of cane sugar calculated using the given molality and the mass of the solution.

Option C ($\mathrm{K}_3 \mathrm{PO}_4$) is correct because it dissociates into 4 ions, resulting in a van't Hoff factor of 4.

The correct answer is C (2:7) because it is calculated using the ratio of Kf/Kb and the squares of the freezing and boiling points.

Option B (Saturated vapour pressure) is correct because it is the pressure exerted by a vapor in equilibrium with its liquid at a given temperature.

Option C (150) is correct because the gram molecular mass of X is calculated by equating the molarities of the isotonic solutions and using the given percentages.

Option C (Sodium phosphate) is correct because it dissociates into the highest number of ions (4), leading to the highest van't Hoff factor.

Option B ($P_{\text {total }} = P_B^{\circ} + (P_A^{\circ} - P_B^{\circ}) X_A$) is correct because it represents Raoult's law for an ideal binary solution, expressing total pressure in terms of mole fraction and vapor pressures of pure components.

The correct answer is D (If both Assertion & Reason are false) because the Van't Hoff factor can be less than 1 for association, and the Reason incorrectly defines the Van't Hoff factor as the inverse ratio.

Option A (Vapour pressure) is correct because vapor pressure itself is not a colligative property, but the *lowering* of vapor pressure is.

Option C (Mol. wt./6) is correct because the equivalent weight is calculated by dividing the molecular weight by the change in oxidation number of iodine in the reaction.

Option D (A supersaturated solution) is correct because a supersaturated solution is a metastable system that can easily precipitate upon disturbance.

Option B ($7.38 \mathrm{~atm}$) is correct because the total osmotic pressure is the sum of the osmotic pressures of urea and cane-sugar, calculated separately using the osmotic pressure formula.

The correct answer is A ($5: 1$) because the ratio of elevation in boiling point is directly proportional to the van't Hoff factor, which is 5 for the complex and 1 for sugar.

Option D (If Statement I is false but Statement II is correct) is correct because the vapor pressure of water at 373 K is equal to 1.013 bar, and water boils when its vapor pressure equals atmospheric pressure.

Option A (0.1) is correct because the partition coefficient in favor of B is the inverse of the partition coefficient in favor of A.

Option D (Both (A) and (R) are false) is correct because the freezing point depression is a colligative property and depends on the number of particles. Glucose and urea are both non-electrolytes, so for the same molarity, they will have the same freezing point depression. Also, Kf is a constant for a given solvent.

Option A (1) is correct because the molality is calculated using the given molarity and density, and the result is closest to 1.

Option C is correct because benzene and toluene are structurally similar and form ideal solutions at low concentrations, and structural similarity is the reason for ideal solution formation.

Option B (9.852 atm) is correct because the osmotic pressure is calculated using the freezing point depression and the ideal gas law.

Option A is correct because for an ideal solution, the volume change upon mixing is zero, which directly explains why the total volume is the sum of individual volumes.