A salt solution sits in an open beaker. Assuming constant temperature and pressure, the vapor pressure of the solution
A) stays the same over time.
B) We need to know which salt is in the solution to answer this.
C) increases over time.
D) We need to know the temperature and pressure to answer this.
E) decreases over time.

Question

Quizplus · Accepted Answer

The vapor pressure of a salt solution in an open beaker decreases over time because as the water evaporates, the solution becomes more concentrated with salt, which lowers its vapor pressure due to the colligative property of lowering vapor pressure by non-volatile solutes.

A Salt Solution Sits in an Open Beaker