devarshi-dt-logo

Question:

Of physisorption or chemisorption, which has a higher enthalpy of adsorption?

Solution:

Physisorption is an exothermic process. However, it is characterized by low enthalpy values (20–40 kJ mol⁻¹) due to weak van der Waals forces of attraction. The activation energy for physisorption is also very low and hence it is practically a reversible process. Chemisorption is also an exothermic process and the enthalpy values are higher (80–240 kJ mol⁻¹) as it involves the formation of chemical bonds.