Compartments A and B are separated by a membrane that is permeable to K+ but not to Na+ or Cl-. At time zero, a solution of KCl is poured into compartment A and an equally concentrated solution of NaCl is poured into compartment B. Which would be true once equilibrium is reached?

8. Compartments A and B are separated by a membrane that is permeable to K+ but not to Na+ or Cl-. At time zero, a solution of KCl is poured into compartment A and an equally concentrated solution of NaCl is poured into compartment B. Which would be true once equilibrium is reached?

A. The concentration of Na+ in A will be higher than it was at time zero.

B. Diffusion of K+ from A to B will be greater than the diffusion of K+ from B to A.

C. There will be a potential difference across the membrane, with side B negative relative to side A.

D. The electrical and diffusion potentials for K+ will be equal in magnitude and opposite in direction.

E. The concentration of Cl- will be higher in B than it was at time zero.

Answer: D. The electrical and diffusion potentials for K+ will be equal in magnitude and opposite in direction.

Explanation:

Diffusion is the movement of molecules from region of higher concentration to lower concentration through a semipermeable membrane.

Since the k+ is the permeable membrane, the k+ ion in the KCl would move in equal magnitude and direction in the solution.