Which of the following is an incorrect statement?

Under what conditions does the rate of physisorption increase?

If $x$ amount of gas is adsorbed on $m$ amount of adsorbent at pressure $p$,the Freundlich adsorption isotherm plot gives a straight line for which of the following?

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 is the role of adsorption in the froth floatation process used especially for the concentration of sulphide ores?

In Langmuir's model of adsorption of a gas on a solid surface: