Question

Write down the differences between diffusion and osmosis.

How does osmosis differ from diffusion?

Answer 1

Sr. No.	Diffusion	Osmosis
1.	Diffusion can occur in any medium.	It occurs only in a liquid medium.
2.	The diffusing molecules may be solids, liquids or gases.	It involves movement of solvent molecules only.
3.	Semipermeable membrane is not required.	Semipermeable membrane is required.
4.	It is dependent upon the free energy of the molecules of the diffusing substance only; the presence of other substances in the system is of no importance.	Though it is the diffusion of solvent molecules only, yet influenced by the presence of other substances (solutes) in the system.
5.	An equilibrium in the free energy of diffusion molecules is achieved in the system.	Equilibrium in the free energy of solvent molecules is never achieved.

Answer 2

Sr. No.	Diffusion	Osmosis
1.	Diffusion involves the free mixing of the solution without a semipermeable membrane.	Osmosis involves the use of a semipermeable membrane.
2.	In diffusion, both solvent and solute molecules move directly into each other. Thus, it is a bilateral process.	In osmosis only solvent molecules move through the semipermeable membrane. The movement of solute particles is checked by the semipermeable membrane.
3.	It can neither be stopped nor reversed.	It can be stopped or reversed by applying external pressure on the solution having a higher concentration.
4.	In diffusion, solute particles move from higher concentration to lower concentration while the solvent molecules move from lower concentration to higher concentration.	In osmosis, the net flow of solvent molecules is from lower concentration to higher concentration.
5.	It is shown by solutions as well as by gases.	It is shown by solutions only.