The Langmuir adsorption isotherm is based on which of the following assumptions?

Which of the following statements is not true?

Arrange the gases $H_2, CH_4, CO_2,$ and $NH_3$ in the order of their volume adsorbed on $1 \ g$ of charcoal at $288 \ K$.

The graph of $\log(x/m)$ versus $\log p$ is a straight line with an angle of $45^o$ and an intercept of $0.3010$ on the $y$-axis. Calculate the amount of gas adsorbed per gram at a pressure of $0.2 \, atm$.

Which among the following gases is least adsorbed on a solid at similar conditions of temperature and pressure?

The correct option$(s)$ related to adsorption processes is(are):
$A$. Chemisorption results in a unimolecular layer.
$B$. The enthalpy change during physisorption is in the range of $100$ to $140 \ kJ \ mol^{-1}$.
$C$. Chemisorption is an endothermic process.
$D$. Lowering the temperature favors physisorption processes.