At the equilibrium position in the process of adsorption ___________. (i) ∆H > 0 (ii) ∆H = T∆S (iii) ∆H > T∆S (iv) ∆H < T∆S
Option 2) The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid is termed adsorption. During adsorption, there is always a decrease in residual forces of the surface, i.e., there is a decrease in surface energy which appears as heat. Hence, adsorption is an exothermic process. So the value of ΔH is -ve On the basis of the equation, ΔG=ΔH−TΔS can be negative if ΔH has sufficiently high negative value as ΔH−TΔS is positive. Thus, in an adsorption process, which is spontaneous, a combination of these two factors makes ΔG negative. As the adsorption proceeds, ΔH becomes less and less negative ultimately ΔH becomes equal to TΔS and ΔG becomes zero. At this state, equilibrium is attained. Thus at equilibrium, ΔH=TΔS
