Question

Assertion : Osmosis is a special type of diffusion of water through a semi-permeable membrane.
Reason : The net direction and rate of osmosis depends only on the pressure gradient.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

Diffusion of water from its pure state (or dilute solution) into a solution (or stronger solution) when the two are separated by a semi-permeable membrane is termed as osmosis. The direction and rate of osmosis depend upon the sum of two forces, pressure gradient (gradient of ${\Psi }_p$) and concentration gradient (gradient of ${\Psi }_s$). The net force or gradient is determined by the difference in the water potentials of solutions separated by a semipermeable membrane.