Which of the following statements is correct for chemisorption?

The following chromatogram was developed by adsorption of compound '$A$' on a $6 \ cm$ $TLC$ glass plate. The retardation factor $(R_f)$ of the compound '$A$' is $.......... \times 10^{-1}$.

What kind of difference is observed in the amount of adsorption with the increase in temperature?

$A$ mixture of substances $A, B, C, D$ is subjected to column chromatography. The degree of adsorption is in the order of $D > B > C > A$. The column is eluted with a suitable solvent. Identify the correct statement with respect to the separation of the mixture.

Assuming Langmuir monolayer adsorption,the volume of nitrogen gas adsorbed on a sample of silica gel at $STP$ is $1.30 \, cm^3 \, g^{-1}$. The area occupied by a nitrogen molecule is $0.16 \, nm^2$. The surface area of silica gel per gram is ......... $m^2 \, g^{-1}$.

$0.2 \ g$ of fine animal charcoal is mixed with half litre of acetic acid solution and shaken for $30 \ minutes$. What happens to the concentration of the acetic acid solution?