In Langumir's model of adosrption of a gas on a solid surface :

Options

A. The rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered
B. The adsorption at a single site on the surface may involve multiple molecules at the same time
C. The mass of gas striking a given area of surface is proportional to the pressure of the gas
D. The mass of gas striking a given area of surface is independent of the pressure of the gas

Explanation

Langmuir adsorption isotherm is based on formation of a monolayer of the adsorbate on the surface of the adsorbent. According to this isotherm the mass of the gas adsorbed per gram of the adsorbent is related to the equilibrium pressure.