Question

Explain why Adsorption is a spontaneous process at low Temperature

Answer 1

Effect of temperature :
Adsorption is an exothermic process and thus according to the Le Chatlier's principle, a decrease in temperature of the system would result in an increase in adsorption.
The above effect of temperature can be understood on the basis of two parameters,the thermal energy of gaseous molecules and the residual forces of the surface.These two parameters act in the opposite directions.If the temperature of the system is large,then because of the larger thermal energy, lesser number of molecules are held to the surface of the solid by the residual forces and hence lesser is the adsorption.At lower temperatures, thermal energy is less and thus more number of molecules remain stick to the surface and hence larger is the adsorption.