. Adsorption can occur in all interfacial faces i.e., the adsorption can occur in between gas – solid, liquid – solid, liquid – liquid, solid – solid and gas – liquid.
2. Adsorption is always accompanied by decrease in free energy. When ∆G reaches zero, the equilibrium is attained.
3. Adsorption is a spontaneous process.
4. When molecules are getting adsorbed, there is always decrease in randomness of the molecules.
∆G = ∆H – T∆S where ∆G = change in free energy
∆H change in enthalpy
∆S change in entropy
∆H = ∆G + T∆S
5. Adsorption is exothermic and it is a quick process.
6. If simultaneous adsorption and absorption take place, it is termed as ‘sorption and sorption of gases on metal surface is called occlusion.