A solution contains 1 mole of liquid A and 3 moles of liquid B.This solution has a vapor pressure of 314 torr at 25°C.At 25°C,liquid A has a vapor pressure of 265 torr and liquid B has a vapor pressure of 355 torr.Which of the following is true?
A)This solution exhibits a positive deviation from Raoult's Law.
B)This solution exhibits a negative deviation from Raoult's Law.
C)This solution is ideal.
D)More information is needed to answer this question.
E)None of these (A-D).

Question

Quizplus · Accepted Answer

The observed vapor pressure of the solution (314 torr) is less than the vapor pressure predicted by Raoult's Law (which would be 1 x 265 torr + 3 x 355 torr = 1340 torr). This indicates a positive deviation from Raoult's Law, which occurs when the intermolecular forces between the components of the mixture are weaker than the forces between like molecules. This allows for more molecules to escape into the gas phase than predicted by Raoult's Law, resulting in a lower observed vapor pressure.

A Solution Contains 1 Mole of Liquid a and 3