Which of the following is not a characteristic of chemisorption?

In Freundlich adsorption,the amount of gas adsorbed is proportional to pressure $P$ as

Adsorption of a gas follows the Freundlich adsorption isotherm. $x$ is the mass of the gas adsorbed on mass $m$ of the adsorbent. The plot of $\log \frac{x}{m}$ versus $\log p$ is shown in the given graph. $\frac{x}{m}$ is proportional to:

If the adsorbate is held on a surface by weak Van der Waals forces,the adsorption process is called:

The correct statement regarding chemisorption is

What will be the effect of an increase in temperature on physical adsorption?