Adsorption is always

Which of the following statements is incorrect regarding physical adsorption?

Which of the following statements is correct for the spontaneous adsorption of a gas?

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.

What do you understand by activation of adsorbent? How is it achieved?

Which one of the following gives a straight line for Freundlich adsorption isotherm?