Match the LIST-I with LIST-II.
| LIST-I (Observations related to solutions) | LIST-II (Equation: Symbols have their usual meanings) |
| A. Henry’s Law | I. \( \Delta p_1=x_2p_1^0 \) |
| B. Relative Lowering of Vapor Pressure | II. \( \Delta T_f=mK_f \) |
| C. Depression of Freezing Point | III. \( p=xK_H \) |
| D. Elevation of Boiling Point | IV. \( \Delta T_b=mK_b \) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A-III, B-I, C-II, D-IV
Each law or colligative property of solutions has its own standard equation. The quickest way to match them is to look at the constant in each equation: KH belongs to Henry’s law, Kf to freezing point and Kb to boiling point.
(A) Henry’s Law — This matches (III) \( p=xK_H \). The partial pressure of a gas above a solution is proportional to its mole fraction in the solution; KH is Henry’s law constant.
(B) Relative Lowering of Vapor Pressure — This matches (I) \( \Delta p_1=x_2p_1^0 \). From Raoult’s law, the lowering of the vapour pressure of the solvent equals the mole fraction of the solute (x2) times the vapour pressure of the pure solvent.
\( \displaystyle \frac{\Delta p_1}{p_1^0}=x_2 \)
(C) Depression of Freezing Point — This matches (II) \( \Delta T_f=mK_f \). Kf is the molal depression constant (cryoscopic constant) and m is the molality.
(D) Elevation of Boiling Point — This matches (IV) \( \Delta T_b=mK_b \). Kb is the molal elevation constant (ebullioscopic constant).
Shortcut: (C)–(II) and (D)–(IV) appear only in Options (1) and (2), and (A)–(III) then leaves only Option (1).