The beaker in the illustration below contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to both salt and water. Which of the following will occur in this container?
A)Net diffusion of water from B to A and of salt from A to B.
B)Net diffusion of water from A to B and of salt from B to A.
C)Net diffusion of water across the membrane, but not of salt.
D)Diffusion of salt across the membrane, but not of water.
E)Net diffusion of salt from B to A, but no net diffusion of water.

Question

The beaker in the illustration below contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to both salt and water.  Which of the following will occur in this container?
A)Net diffusion of water from B to A and of salt from A to B. 
B)Net diffusion of water from A to B and of salt from B to A. 
C)Net diffusion of water across the membrane, but not of salt. 
D)Diffusion of salt across the membrane, but not of water. 
E)Net diffusion of salt from B to A, but no net diffusion of water.

Quizplus · Accepted Answer

This is an example of osmosis, where water will move from an area of low solute concentration to an area of high solute concentration. In this case, Solution A has a higher concentration of salt (higher solute concentration) than Solution B, so water will move from Solution B to Solution A, resulting in a net diffusion of water from A to B. At the same time, the salt will diffuse from Solution A to Solution B down its concentration gradient. Therefore, there will be a net diffusion of salt from B to A.

The Beaker in the Illustration Below Contains Two Solutions of Salt