Match List-I with List-II List-I Term List-II Formula/expression (A)…

The correct answer is Option (1) → (A)-(IV), (B)-(III), (C)-(II), (D)-(I)

All four expressions describe the vapour above a solution. Raoult’s law relates the partial vapour pressure of a component to its mole fraction in the solution; Dalton’s law adds the partial pressures; Henry’s law gives the solubility of a gas; and the relative lowering of vapour pressure follows from Raoult’s law for a solution of a non-volatile solute.

• (A) Raoult's law — This matches (IV) \( P_2 = P_2^0 x_2 \). The partial vapour pressure of each volatile component is its pure vapour pressure multiplied by its mole fraction in the solution.

• (B) Henry's Law — This matches (III) \( p = K_Hx \). The partial pressure of a gas over a solution is proportional to its mole fraction in the solution; \( K_H \) is the Henry’s law constant.

• (C) Dalton's Law of partial pressure — This matches (II) \( P_{total} = P_1^0 + (P_2^0- P_1^0) x_2 \). The total pressure is the sum of the partial pressures; with Raoult’s law and \( x_1 = 1 - x_2 \):

      \( \displaystyle p_{total} = p_1^0 x_1 + p_2^0 x_2 = p_1^0 (1 - x_2) + p_2^0 x_2 = p_1^0 + (p_2^0 - p_1^0)\,x_2 \)

• (D) Relative lowering of vapor pressure — This matches (I) \( \frac{P_1^0-P_1}{P_1^0}=x_2 \). With a non-volatile solute, \( p_1 = p_1^0 x_1 = p_1^0 (1 - x_2) \), so the lowering divided by \( p_1^0 \) equals the mole fraction of the solute:

      \( \displaystyle \frac{p_1^0 - p_1}{p_1^0} = x_2 \)

Shortcut: (A)-(IV) appears in Options (1) and (4), and (B)-(III) then leaves only Option (1).

Note: The same/similar question has been asked in different years by NTA as per the details given below: