Question

What is the sign of delta h,delta s and delta g,when a gas is adsorbed by an adsorbent and whan delta g becomes zero

Answer 1

Heya,

Thanks for the question.

1. When a gas is adsorbed , there is a decrease in entropy .Hence, ∆S is positive.
2. There is a decrease in surface energy, hence it appears as heat.So, ∆H is negative.
3. Since, ∆G = ∆H - T∆S from (1) and (2) , ∆G is negative.

∆G becomes zero at equilibrium when further there is no adsorption.

Regards