Question

Cell ‘A’ with OP = 10 atm and TP = 5 atm is in contact with cell ‘B’ having OP = 15 atm and TP = 12 atm. The flow of water will be

• A. from A to B
• B. equal flow
• C. from B to A
• D. no flow

Answer 1

The correct option is C from B to A

We know that,
DPD = OP - TP

In cell A: DPD = 10 - 5 = 5 atm
In cell B: DPD = 15 - 12 = 3 atm

Diffusion pressure deficit (DPD) is the reduction in diffusion pressure (DP) of water in a system over its pure state. Diffusion pressure is the pressure exerted by the molecules that are undergoing diffusion. DP of pure solvent is maximum. DPD determines the direction of movement of water. Water always moves from an area of lower DPD to the area or cell of higher DPD.
In this case cell B has a lower DPD than cell A. Thus, the flow of water will be from cell B to A.