There are various factors that affect the rate of adsorption of a gas on a solid surface. The factors are as follows:

(1) Nature of the gas:

Easily liquefiable gases such as NH₃, HCl, etc. are adsorbed to a great extent in comparison to gases such as ${\mathrm{H}}_2, {\mathrm{O}}_{\mathrm{2,}}$ etc. This is because Van der Waal’s forces are stronger in easily liquefiable gases.

(2) Surface area of the solid

The greater the surface area of the adsorbent, the greater the adsorption of a gas on the solid surface. 

(3) Effect of pressure

Adsorption is a reversible process and is accompanied by a decrease in pressure. Therefore, adsorption increases with an increase in pressure. 

(4) Effect of temperature

Adsorption is an exothermic process. Thus, in accordance with Le-Chatelier’s principle, the magnitude of adsorption decreases with an increase in temperature.