Which inert gas is used in chromatography?

On which factors does the amount of adsorption depend?

Assertion $(A)$: Adsorption is an exothermic process.
Reason $(R)$: Physisorption of a gas on a solid surface is normally reversible.

In Freundlich adsorption isotherm at moderate pressure,the extent of adsorption $\left(\frac{x}{m}\right)$ is directly proportional to $P^x$. The value of $x$ is

Which of the following gases will be adsorbed to a greater extent on the surface of charcoal?

Choose the correct statement for chemical adsorption.