What should be taken on the $Y$-axis in the Freundlich adsorption isotherm plot to obtain a straight line?

What is the effect of pressure on the extent of adsorption?

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ Amongst $He$,$Ne$,$Ar$ and $Kr$; $1 \ g$ of activated charcoal adsorbs more of $Kr$.
Reason $R$: The critical volume $V_c \left( cm^3 \ mol^{-1} \right)$ and critical pressure $P_c \left( atm \right)$ is highest for Krypton but the compressibility factor at critical point $Z_c$ is lowest for Krypton.
In the light of the above statements,choose the correct answer from the options given below.

Which of the following is not a characteristic of chemisorption?

Which type of adsorption leads to the formation of a multimolecular layer?

Which of the following statements is true for physical adsorption?