Question

Explain how the adsorption of a gas on solid varies with the nature of adsorbate and adsorbent.

Answer 1

• Nature of adsorbate:

1. All solids adsorb gases to some extent. It is observed that gases having high critical temperature liquefy easily and can be readily adsorbed.
2. The gases such as SO₂, Cl₂, NH₃ which are easily liquefiable are adsorbed to a larger extent as compared to gases such as N₂, O₂, H₂, etc. which are difficult to liquify.
3. Thus, the amount of gas adsorbed by a solid depends on the nature of the adsorbate gas i.e., whether it is easily liquefiable or not.

• Nature of adsorbent:
  Substances that provide large surface area for a given mass are effective as adsorbents and adsorb appreciable volumes of gases. e.g. Silica gel and charcoal are effective adsorbents due to their porous nature.