A solution contains 1 mol of liquid A and 3 mol of liquid B. The vapor pressure of this solution is 314 torr at 25°C. At 25°C, the vapor pressure of liquid A is 265 torr and the vapor pressure of liquid B is 355 torr. Which of the following is true?
A) This solution exhibits a positive deviation from Raoult's law.
B) This solution is ideal.
C) This solution exhibits a negative deviation from Raoult's law.

Question

Quizplus · Accepted Answer

The actual vapor pressure of the solution (314 torr) is lower than the vapor pressure predicted by Raoult's law based on the composition of the solution [(1/4) x 265 torr + (3/4) x 355 torr = 342 torr]. Therefore, the solution exhibits a negative deviation from Raoult's law.

A Solution Contains 1 Mol of Liquid a and 3