Question

Chose the correct option regarding adsorption?

• A. Adsorption is accompained by decrease in enthalpy of the system and increase in entropy of the system
• B. Adsorption is accompained by increase in enthalpy and increase in entropy of the system
• C. Adsorption is accompained by decrease in enthalpy and decrease in entropy of the system
• D. Adsorption is accompained by increase in enthalpy and decrease in entropy of the system

Answer 1

The correct option is C Adsorption is accompained by decrease in enthalpy and decrease in entropy of the system

During adsorption, there is always a decrease in residual forces of the surface, i.e., there is decrease in surface energy which appears as heat. Adsorption, therefore, is invariably an exothermic process. When a gas is adsorbed, the freedom of movement of its molecules become restricted. This leads to decrease in the entropy of the gas after adsorption. Adsorption is thus accompanied by decrease in enthalpy as well as decrease in entropy of the system