(N/A) There are various factors that affect the rate of adsorption of a gas on a solid surface:
$1$. Nature of the gas:
Easily liquefiable gases such as $NH_3$ and $HCl$ are adsorbed to a greater extent compared to gases like $H_2$ and $O_2$. This is because van der Waals forces are stronger in easily liquefiable gases.
$2$. Surface area of the solid:
The greater the surface area of the adsorbent,the greater is the adsorption of a gas on the solid surface.
$3$. Effect of pressure:
Adsorption is a reversible process. According to Le Chatelier's principle,an increase in pressure leads to an increase in the extent of adsorption.
$4$. Effect of temperature:
Adsorption is an exothermic process. Therefore,in accordance with Le Chatelier's principle,the magnitude of adsorption decreases with an increase in temperature.