Give uses of silica gel.

Freundlich adsorption isotherms for the physical adsorption of a gas at temperatures $T_1$,$T_2$ and $T_3$ are shown in the graph given below. The correct relationship between $T_1$,$T_2$ and $T_3$ is:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: In expensive scientific instruments,silica gel is kept in watch-glasses or in semipermeable membrane bags.
Reason $(R)$: Silica gel adsorbs moisture from air via adsorption,thus protects the instrument from water corrosion (rusting) and/or prevents malfunctioning.
In the light of the above statements,choose the correct answer from the options given below:

Which one of the following is not applicable to chemisorption?

What is an adsorption isotherm? Describe Freundlich adsorption isotherm.

Which of the following statements is not correct in respect of chemisorption?