Question

Justify with reasons: (i) Why does physical adsorption decrease on increasing temperature?
(ii) Why are powdered materials better effective adsorbents in comparison to their crystalline forms?

Hint:

Remember: Adsorption is surface phenomenon, and higher surface area leads to higher adsorption.

Answer 1

(i) Explanation.
Physical adsorption is exothermic in nature. According to Le Chatelier’s principle, increasing temperature decreases the extent of exothermic processes, hence adsorption decreases.
(ii) Explanation.
Powdered materials have more surface area exposed compared to crystalline solids. Adsorption being a surface phenomenon, greater surface area enhances adsorption.
Conclusion.
(i) Adsorption decreases with temperature.
(ii) Powdered form acts as a better adsorbent due to large surface area.