Question

Write four differences between physical adsorption and chemical adsorption.

Answer 1

Four differences between physical adsorption and chemical adsorption:

Physical adsorption	Chemical adsorption
1. The forces between the adsorbate molecules and the adsorbent are weak van der Waal’s forces.	1. The forces between the adsorbate molecules and the adsorbent are strong chemical forces similar to chemical bonding.
2. Low enthalpy of adsorption of the order of 2O to 4O kJ mol-1	2. High enthalpy of adsorption of  the order of 80 to 240kJ mol-1.
3. Usually occurs at low temperature and decreases with increase in temperature.	3. It occurs at high temperature and increases with the increase in temperature.
4. It is reversible in ture.	4. It is irreversible.