Question

Vessel-1 contains \(w_2g\) of a non-volatile solute \(X\) dissolved in \(w_1g\) of water. Vessel-2 contains \(w_2g\) of another non-volatile solute \(Y\) dissolved in \(w_1g\) 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.

Answer 1

Correct answer: 150

Vessel-I

\(\mathrm{(\Delta T_b)_I = i_X\frac{w_2}{M_X} .\frac1{w_1} \times 1000\times K_b}\)

\(\mathrm{M_X}\) = Molar mass of ‘X’

Vessel-II

\(\mathrm{(\Delta T_b)_{II } = i_Y\frac{w_2}{M_Y} .\frac1{w_1} \times 1000\times K_b}\)

\(\mathrm{M_Y}\) = Molar mass of ‘Y’

\(\mathrm{\frac{(\Delta T_b)_I}{(\Delta T_b)_{II}} \times 100 = \frac{i_X}{i_Y}. \frac{M_Y}{M_X} \times 100}\)

\(= 1.2 \times \frac{100}{80} \times 100\)

\(= 150\) %