Question

how does free energy and entropy chages during adsorption​

Answer 1

During adsorption, enthalpy and entropy of the system are negative but ΔG must be negative so that the process is spontaneous. Adsorption is accompanied by decrease in the free energy of the system as it is a spontaneous process. When ΔG becomes zero, adsorption equilibrium is established. Since it is an exothermic process, ΔH is negative. Since the adhering of gas molecules to the surface lowers the randomness, the ΔS is negative.

Hope it helps you