Match List-I with List-II
| List-I | List-II | ||
|---|---|---|---|
| (A) | Raoult's law | (I) | \(p=k_{H}.x\) |
| (B) | Henry's law | (II) | \(\Delta T_{f}=K_{f}m\) |
| (C) | Elevation of boiling point | (III) | \(p=x_{1}p_{1}^{\circ}+x_{2}p_{2}^{\circ}\) |
| (D) | Depression in freezing point | (IV) | \(\Delta T_{b}=K_{b}m\) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Each law or colligative property in List-I is matched with the equation that expresses it.
(A) Raoult’s law — this matches (III) \(p=x_{1}p_{1}^{\circ}+x_{2}p_{2}^{\circ}\). In a solution of two volatile liquids, the partial vapour pressure of each is its mole fraction times its vapour pressure when pure, and the total pressure is their sum.
(B) Henry’s law — this matches (I) \(p=k_{H}.x\). The partial pressure of a gas over a solution is proportional to its mole fraction in the solution, \(k_H\) being Henry’s law constant; this is why more gas dissolves at higher pressure.
(C) Elevation of boiling point — this matches (IV) \(\Delta T_{b}=K_{b}m\). A non-volatile solute raises the boiling point in proportion to the molality \(m\); \(K_b\) is the ebullioscopic constant.
(D) Depression in freezing point — this matches (II) \(\Delta T_{f}=K_{f}m\). A solute lowers the freezing point in proportion to the molality; \(K_f\) is the cryoscopic constant.