During the adsorption of krypton on activated charcoal at low temperature

Options

A. `DeltaHgt0 "and" DeltaSlt0`
B. `DeltaHlt0 "and" DeltaSlt0`
C. `DeltaHgt0 "and" DeltaSgt0`
D. `DeltaHlt0 "and"DeltaSgt0`

Answer

B

Explanation

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 invariable accompanied by evolution of heat i.e., it is an exothermic process, when a gas is adsorbed, the freedom of movement of its molecules becomes restricted. This amounts to decrease in entropy of the gas after adsorption i.e., S ∆ is negative. Adsorption is thus, accompanied by decrease in enthalpy as well decrease in entropy of the system.