Adsorption of gases on solid surfaces is an ________ process.
- Endothermic
- Exothermic
- Isothermal
- Adiabatic
Answer: Exothermic
Adsorption releases heat (ΔH < 0) as gas molecules lose freedom on surface. Desorption is endothermic. Important for catalysis and purification processes. [[NCERT Chemistry Class 12]]