Question

Potato slices are immersed in a series of solution of different osmotic concentrations. No change in volume or weight is observed with slices in a 0.3 M solution. The osmotic concentration of vacuolar sap, therefore, is

• A. 0.3 M
• B. Greater than 0.3 M
• C. Less than 0.3 M
• D. Not related at all to the outside solution

Answer 1

The correct option is A 0.3 M

Osmosis is diffusion of solvent (water) from region of its high concentration to region of its low concentration through semi-permeable/selectively permeable membrane.
If there is no movement of solvent between two solutions which are separated by S.P.M it means they have the same concentration and are called isotonic solutions.
So the osmotic concentration of cell sap is 0.3 M, because the potato slice neither gains water through endosmosis nor loses water through exosmosis.