Write three distinct features of chemisorptions which are not found in physisorptions.

Answer

Chemisorption is a kind of adsorption which involves a chemical reaction between the surface and the adsorbate.

Physisorption, also called physical adsorption, is a process in which the electronic structure of the atom or molecule is barely perturbed upon adsorption.

S. No.	Point of difference	Physiosorption	Chemisorption
(i)	Specificity	This is not specific in nature.	This is highly specific in nature.
(ii)	Temperature dependence	Low temperature is favourable for physiosorption. It decreases with increase in temperature.	High temperature is favourable for chemisorption. It increases with the increase in temperature.
(iii)	Reversibility	This is reversible in nature.	This is irreversible in nature.
(iv)	Enthalpy change	Enthalpy of adsorption is low.	Enthalpy of adsorption is high.