Question

At 35°C a liquid solution containing 40.5 mol % ethanol and 59.5 mol % methylcyclo-hexane exerts a pressure of 152.4 mmHg. The vapour phase composition is 54.7 mol % ethanol and 45.3 mol % methylcyclo-hexane. The vapour pressures of the pure compounds at 35°C are 103.1 mmHg and 73.6 mmHg for ethanol and methylcyclo-hexane respectively. Using Van Laar model, estimate the mol fraction of ethanol in the vapour phase in equilibrium with a liquid phase containing 60 mol % ethanol at 35°C. Assume azeotrope.

Answer 1