Which one of the following is an incorrect statement for physisorption?

Which of the following statements is incorrect?

Which of the following relationships is correct regarding the Freundlich adsorption isotherm?
$(1)$ $x/m = \text{constant}$ (at high pressure)
$(2)$ $x/m = k \cdot P^{1/n}$ (at intermediate pressure)
$(3)$ $x/m = k \cdot P$ (at low pressure)

The colloidal sol of $SnCl_4$ prefers the adsorption of which ion in the presence of excess $HCl$?

The correct option representing a Freundlich adsorption isotherm is

Which inert gas is used in chromatography?