Question

Why adsorption is always exothermic?

Answer 1

1. Adsorption is the surface phenomenon in which the accumulation of substance occurs on the surface.
2. For adsorption, two components are required, adsorbate and adsorbent.
3. Adsorbates are the substance attached to the surface of another substance.Example-${\mathrm{H}}_2,{\mathrm{O}}_2\mathrm{and}{\mathrm{N}}_2$gas.
4. The adsorbent is the surface on which adsorbate adsorbs. Example-Charcoal, Silica gel, Alumina.
5. As the particles present on the surface of the adsorbent are very less stable and as the adsorbate adsorbs to the surface of the adsorbent, the energy of the adsorbent decreases which in turn releases heat and therefore Adsorption is an exothermic reaction.