Which forms multimolecular layers during adsorption?

Which one of the following is present in gas mask?

Which of the following statements is incorrect regarding physisorption?

Which of the following statements is correct for physisorption?

$CO_{2}$ 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 statements is false during the adsorption of gas molecules on a metal surface?