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 $.......... \times 10^{-1}$.

For the adsorption of a gas on a solid adsorbent,which of the following is positive?

In an adsorption experiment, a graph between $\log (x/m)$ vs $\log P$ was found to be linear with a slope of $45^{\circ}$. The intercept on the $\log (x/m)$ axis was found to be $0.3$. The amount of the gas adsorbed per gram of charcoal under a pressure of $1 \ atm$ is:

Which statements among the following are correct?
$(i)$ Freundlich isotherm fails at high pressure of the gas.
$(ii)$ $\Delta H < 0$ for both physical and chemical adsorption.
$(iii)$ Physical adsorption is non-selective.
$(iv)$ Chemical adsorption is reversible,whereas physical adsorption is irreversible.

Which of the following gases is adsorbed to maximum extent?

Assertion : The enthalpy of physisorption is greater than chemisorption.
Reason : Molecules of adsorbate and adsorbent are held by van der Waal's forces in physisorption and by chemical bonds in chemisorption.