Which forms multimolecular layers during adsorption?

$CO_{2}$ gas adsorbs on charcoal following Freundlich adsorption isotherm. For a given amount of charcoal,the mass of $CO_{2}$ adsorbed becomes $64$ times when the pressure of $CO_{2}$ is doubled. The value of $n$ in the Freundlich isotherm equation is $......\,\times 10^{-2}$. (Round off to the Nearest Integer)

Which of the following is zero during the process of adsorption?

What is an adsorption isotherm? Describe Freundlich adsorption isotherm.

Identify the gas which is readily adsorbed by activated charcoal.

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