Solutions practice · Mixed difficulty

Option D (Both (1) and (3 )) is correct because the solvent is present in large excess and determines the physical state of the solution.

Option A ($\frac{{P}^0-{P}}{P^0}=\frac{{n}}{{N}}$) is correct because it represents the correct mathematical expression of Raoult's law for non-volatile solutes.

Option A is correct because it correctly relates the degree of dissociation to the van't Hoff factor for a weak electrolyte.

Option B (Both A & R are true, R is not correct explanation of A) is correct because azeotropic mixtures are indeed formed by non-ideal solutions, and the vapor phase composition is the same as the liquid phase, but the latter doesn't explain the former.

Option D is correct because Statement I is false (molarity is not always greater than molality) and Statement II is correct (the ratio of molarity and molality depends on the density of the solvent).

Option C (Assertion is true but Reason is false) is correct because osmotic pressure is a colligative property, and the osmotic pressure of 0.1 N urea is less than that of 0.1 M NaCl.

Option B (Raoult's law) is correct because it relates partial pressure and mole fraction in ideal solutions.

A solution that boils at a constant temperature is called an azeotrope, making option A the correct answer. Azeotropes are mixtures with a fixed boiling point.

Option C (Molal ebullioscopic constant) is correct because it is the elevation in boiling point for a one molal solution.

Option D (The concentration of the solute in both the solvents must be kept high) is wrong because the distribution law is most accurate at low solute concentrations.

Option D ($0 \le {x_2} \le 1$) is correct because if one component follows Raoult's law over the entire range, the other component must also follow Raoult's law over the entire range for the solution to be ideal.

Option A (8) is correct because there are 8 possible combinations of dispersed phase (solid, liquid, gas) and dispersion medium (solid, liquid, gas), excluding gas in gas.

Option B ($68 \% \mathrm{~HNO}_3, 32 \% \mathrm{~H}_2 \mathrm{O}$ by mass) is correct because the azeotropic mixture of nitric acid and water contains approximately 68% nitric acid by mass.

Option D (All the above statements are correct) is correct because the total vapor pressure is less than expected from Raoult's law, indicating negative deviation, which lowers the boiling point and implies weaker A-B interactions.

Option C ($A - B$ attraction force remains same as $A - A$ and $B - B$) is correct because this is the condition for a solution to follow Raoult's law.

Statement I is correct, and Statement II is incorrect, making option C the correct answer. Urea is a non-volatile solute, and volatile solutes lower the boiling point.

Option A (Moist air) is correct because it contains water (liquid) dispersed in air (gas).

Option B is correct because both the assertion and reason are true, but the reason explains the effect of temperature on volume, not the fundamental definition of molarity.

Option A (50 %) is correct because the percentage dissociation is calculated by comparing the observed and theoretical colligative properties.

Option A ($- 2.3 \times {10^{ - 2}}$) is correct because it is the calculated freezing point depression using the colligative properties formula, van't Hoff factor, and given constants.

Option A is correct because barium hydroxide, being a strong electrolyte, dissociates into three ions in solution.

Option C ($A > B > C$) is correct because the relative lowering of vapor pressure is a colligative property that depends on the number of moles of solute, and A has the most moles for the same mass.

Option B (1.8) is correct because the van't Hoff factor is calculated based on the ionization of K2HgI4 into ions.

Option D is correct because according to Henry's law, the partial pressure of a gas is proportional to its mole fraction in the solution. Using the given Henry's constant for δ and the molality, we can calculate the pressure, which is approximately 250 kbar.

Camphor has a high molal depression constant, which leads to a significant depression in freezing point even for small amounts of solute, making option C the correct answer. This makes it suitable for determining the molecular weight of non-volatile solutes using the Rast method.

Option A is correct because the degree of dissociation is related to the van't Hoff factor and the number of ions produced.

Option D is correct because the molal depression constant ($K_f$) is calculated by dividing the freezing point depression ($\Delta T_f$) by the molality (m).

Option B ($BaC{l_2}$) is correct because it dissociates into 3 ions, resulting in the highest van't Hoff factor and thus the maximum boiling point elevation.

Option D (All of the above) is correct because all the listed conditions are necessary for Henry's law to be valid.

Option A ($\frac{1}{{76}}$) is correct because it is calculated using Raoult's Law and the definition of mole fraction.