Question

What is “semi-permeable membrane”?

Answer 1

Semi-permeable membrane - A membrane through which only smaller molecules like water can pass but not the bigger molecules like solutes is known as semi-permeable membranes (SPM).

Semi-permeable membranes can be of animal or vegetable origin, and these occur naturally such as pig’s bladder or parchment or can be synthetic such as cellophane.
These membranes appear to be continuous sheets or films, yet they contain a network of sub-microscopic holes or pores through which smaller solvent molecules can pass.

Examples: Cellulose acetate, potassium ferrocyanide, etc.