The vapor pressures of pure propyl alcohol and isopropyl alcohol are 21.0 mmHg and 45.2 mmHg, respectively, at 25°C. What is the composition of the vapor in equilibrium with a propyl alcohol - isopropyl alcohol solution in which the mole fraction of propyl alcohol is 0.250?

Question

Quizplus · Accepted Answer

The vapor composition can be calculated using Raoult's Law. The partial pressure of each component is the product of its mole fraction in the liquid and its vapor pressure. The mole fraction of each component in the vapor is then the partial pressure of that component divided by the total pressure.

The Vapor Pressures of Pure Propyl Alcohol and Isopropyl Alcohol