a) What are the two types of adsorption of gases on solids? b) Write any two characteristics of each of the above two types of adsorption.

Question

There are mainly two types of adsorption of gases on solids

a) What are the two types of adsorption of gases on solids?

b) Write any two characteristics of each of the above two types of adsorption.

Answer 1

a) Physical adsorption or physisorption and chemical adsorption or chemisorption,

b)

PhysicalAdsorption	ChemicalAdsorption
1. Adsorbate  molecules are held on the surface of the adsorbent by weak vander wall's forces	1. The adsorbate molecules are held on the surface of the adsorbent by chemical bonds
2. Not specific in nature	2. Highly specific in nature
3. Low temperature  is favourable for adsorption	3. High temperature is favourable for adsorption
4. Enthalpy of adsorpiton is low (20-40 kJ mol-1)	4. Enthalpy of adsorption is high (80-240 KJ mol-1)