Question:

Which of the following statement is incorrect regarding physisorption?

More easily liquefiable gases are adsorbed readily.

It occurs because of Van der Waals' forces.

Under high pressure, it results into multi molecular layer on adsorbent surface.

Enthalpy of adsorption(ΔHadsorption)is low and positive.

Solution:

Enthalpy of adsorption in physisorption is negative as the process is exothermic. Physisorption is a process where the adsorbate molecules are held to the surface of the adsorbent by weak van der Waals forces. The formation of these weak bonds releases energy, making the process exothermic and resulting in a negative enthalpy of adsorption (ΔHadsorption).