Question

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

Answer 1

Physisorption is an exothermic process. However, it is characterized by low enthalpy values $(20–40kJmo{l}^{-1})$ 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 $(80-240kJmo{l}^{-1}$) as it involves formation of chemical bonds.