Question

The beaker is divided into two chambers A and B. The big circle represents solute and the small circles solvent.

(i) What can you say about the size of the holes in the membrane, if it is to behave semi- permeably between these two?
(ii) Will the solvent molecules pass through the membrane from left to right, from right to left, in either direction or in both directions?
(iii) In which direction will there be a net movement of solvent molecules?

Answer 1

(i) The size of the holes in the membrane is large enough to allow only the solvent particles to pass through it. But solute particle cannot pass through it. Thus, the membrane acts as the semi-permeable.
(ii) Solvent molecules will pass through the membrane in both directions. Since solvent molecules are present on both the sides they will strike the semi-permeable membrane and pass through the same.
(iii) There is a net movement of solvent molecules from the place of its higher chemical potential to the place of its lower chemical potential, i.e., from right to left.