JEE Advanced 2024 Paper 2 · Q09 · Solutions & Colligative Properties

Question

Vessel-1 contains $w_2$ g of a non-volatile solute X dissolved in $w_1$ g of water. Vessel-2 contains $w_2$ g of another non-volatile solute Y dissolved in $w_1$ g of water. Both the vessels are at the same temperature and pressure. The molar mass of X is 80% of that of Y. The van't Hoff factor for X is 1.2 times of that of Y for their respective concentrations.
The elevation of boiling point for solution in Vessel-1 is _____ % of the solution in Vessel-2.

SolveKar AI · Accepted Answer

$\Delta T_b = i\, k_f\, m$ where $m = \dfrac{w_2/M}{w_1/1000}$. So $\dfrac{\Delta T_{b,1}}{\Delta T_{b,2}} = \dfrac{i_X}{i_Y}\cdot\dfrac{M_Y}{M_X} = 1.2 	imes \dfrac{1}{0.8} = 1.5$. Hence Vessel-1's elevation is $150\%$ of Vessel-2's.