Adsorption- The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid is termed as adsorption. In this substance accumulate at surface only and does not penetrate into the adsorbent (material on the surface of which adsorption takes place)

Ex.-If gases like O₂, H₂, NH₃ taken in a closed vessel containing charcoal then gases get adsorbed on the surface of charcoal and reduce the pressure.

Absorption- In this molecules get distributed uniformly throughout the material Instead of accumulating at the surface.

Ex- When gas like O₂ is mixed with water then O₂ get distributed throughout the solvent (Water).