# Concept Revisor : Solutions

**Chemistry**Level 3

The molar volume of liquid benzene with density \(\rho = 0.877\text{ g/ml}\) increases by \(2750\) times as it vapourises at \(20^\circ\text{C}. \)

At \(27 ^{ \circ } \text{C} \) when a non-volatile non-dissociating solute is dissolved in \(54.6\text{ ml}\) of benzene, the vapour pressure of the solution is found to be \(98.88\text{ mmHg}.\)

Calculate the freezing point (in degrees Celsius) of the solution.

**Details and Assumptions**

- The enthalpy of vapourisation of liquid benzene is \(394.57\text{ J g}^{-1}.\)
- The enthalpy of fusion of liquid benzene is \(10.06\text{ kJ mol}^{-1}.\)
- The freezing point of pure benzene is \(5.5 ^{ \circ } \text{C}. \)