Question

What is Osmosis? How does it differ from diffusion?

Answer 1

Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane from the region of higher solvent concentration to low solvent concentration, in the direction that tends to equalize the solute concentrations on the two sides.

One important difference between osmosis and diffusion is that both solvent and solute particles are free to move in diffusion, but when we talk about osmosis, only the solvent molecules(water molecules) cross the membrane. Osmosis is limited to solutions only, whereas diffusion can take place in liquids, gases, and solutions.

Also, the presence of a semipermeable membrane is a specific property of osmosis, whereas diffusion can occur even without a semipermeable membrane.