Which of the following is not a characteristic of physical adsorption?

According to the Freundlich adsorption isotherm,which of the following is correct?

$A$ plot of $\log (x / m)$ versus $\log (P)$ for the adsorption of a gas on a solid gives a straight line with a slope of:

The volumes of gases $H_2, CH_4, CO_2$ and $NH_3$ adsorbed by $1 \ g$ of charcoal at $288 \ K$ are in the order:

Given below are two statements. One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A :$ Activated charcoal adsorbs $SO_{2}$ more efficiently than $CH_{4}$.
Reason $R$ : Gases with lower critical temperatures are readily adsorbed by activated charcoal.
In the light of the above statements,choose the correct answer from the options given below.

Give an example where physisorption changes to chemisorption with rise in temperature. Explain the reason for change.