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. Therefore the osmotic concentration of vacuolar sap is

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

Answer 1

The correct option is A 0.3 M

During osmosis, water flows from a region of its higher concentration (dilute solution) to a region of its lower concentration (concentrated solution), across a semipermeable membrane.

If there is no movement of water across the membrane, it means the two solutions have identical osmotic concentrations i.e., they are isotonic.

For example in this case we conclude that the osmotic concentration of cell sap is 0.3 M, because the potato slice neither gains water through endosmosis nor loses water through exosmosis.