Question

Adsorption of a gas on solid metal surface is spontaneous and exothermic, then :

• A. $\Delta H$ increases
• B. $\Delta S$ increases
• C. $\Delta G$ increases
• D. $\Delta S$ decreases

Answer 1

The correct option is D $\Delta S$ decreases

Adsorption of a gas on solid metal surface is spontaneous and exothermic, then $\Delta S$ decreases.

Since for spontaneous and exothermic process, $\Delta G=-ve,\Delta H=-ve$ at all temperatures.

Therefore, from $\Delta G=\Delta H-T\Delta S,\Delta S$ should be $-ve$.

Also, adsorption of gas on solid surface gives more orderly arrangement.