In a plot of $\log \left( \frac{x}{m} \right)$ $vs$ $\log p$,for the adsorption of a gas on a solid,a straight line is obtained. The slope of that straight line is

The rate of physical adsorption increases with......

The following statements relate to the adsorption of gases on a solid surface. Identify the incorrect statement among them.

Two statements are given below.
Statement-$I$: Adsorption of a gas on the surface of charcoal is primarily an exothermic reaction.
Statement-$II$: $A$ closed vessel contains $O_2, H_2, Cl_2, NH_3$ gases. Its pressure is $P \ atm$. About $1 \ g$ of charcoal is added to this vessel and after some time its pressure was found to be less than $P \ atm$.
The correct answer is:

For the adsorption of a gas on a solid,the slope of the linear plot of $\log(x/m)$ versus $\log(p)$ is .... ($n$ is an integer).

Why does physical adsorption decrease with an increase in temperature?