Rising temperature has an opposite effect on physisorption and chemisorption. Explain the reason.

Explanation

Physical adsorption involves weak van der Waals' forces. These forces become less effective at higher temperatures. As a result, the extent of physical adsorption decreases with rise in temperature. On the other hand, chemical adsorption involves formation of chemical bonds. This requires a high energy of activation, which is usually acquired by the reactant molecules at higher temperature. This is why chemisorption occurs at a greater extent at high temperature. However, if the temperature becomes very high, the extent of chemisorption decreases.