Which of the following is not a characteristic of chemisorption?

$CH_4$ is adsorbed on $1 \ g$ charcoal at $0^{\circ} C$ following the Freundlich adsorption isotherm. $10.0 \ mL$ of $CH_4$ is adsorbed at $100 \ mm$ of $Hg$,whereas $15.0 \ mL$ is adsorbed at $200 \ mm$ of $Hg$. The volume of $CH_4$ adsorbed at $300 \ mm$ of $Hg$ is $10^x \ mL$. The value of $x$ is $....\times 10^{-2}$ (Nearest integer). [Use $\log_{10} 2=0.3010, \log_{10} 3=0.4771$]

Plot of $\log \left( \frac{x}{m} \right)$ against $\log P$ is a straight line inclined at an angle of $45^o$. When the pressure is $0.5 \ atm$ and Freundlich parameter,$k$ is $10$,the amount of solute adsorbed per gram of adsorbent will be ...... $g$ $(\log 5 = 0.6990)$

Why is the adsorption of a gas on a solid exothermic?

Which of the following is $NOT$ a characteristic of chemisorption?

The Freundlich adsorption isotherm gives a straight line on plotting: