Question

Choose the correct statement(s) regarding adsorption of gases on solids:

• A. The extent of adsorption of a gas depends on pressure of the gas.
• B. The extent of adsorption of a gas does not depend on pressure of the gas.
• C. As the temperature increases, adsorption is favoured.
• D. As the temperature increases, desorption is favoured.

Answer 1

Answer: (A), (D)

As the temperature increases, desorption is favoured.

Effect of Temperature
Since
Adsorption is exothermic and desorption is endothermic.
Also,
$\text{Adsorbent (s) + Adsorbate (g)}\rightleftharpoons \text{[Adsorbent--Adsorbate] +}\Delta H$
Here ,
$\Delta H<0$
According to Le-Chatelier's principle
An increase in temperature favours desorption

Adsorption Isotherm
The variation in the amount of gas adsorbed by the adsorbent with pressure can be expressed by a curve termed as adsorption isotherm.
Extent of adsorption (x/m) increases with pressure.
It becomes maximum corresponding to a pressure $P_s$, called as saturation pressure