Which one of the following substances adsorbs hydrogen gas most strongly?

$2.0 \, g$ of $H_2$ gas is adsorbed on $2.5 \, g$ of platinum powder at $300 \, K$ and $1 \, bar$ pressure. The volume of the gas adsorbed per gram of the adsorbent is $..... \, mL$.
(Given: $R = 0.083 \, L \, bar \, K^{-1} \, mol^{-1}$)

The graph drawn between $\log \left(\frac{x}{m}\right)$ and $\log (p)$ is shown below with intercept $OA = 0.3010$. What is the value of $\left(\frac{x}{m}\right)$ at a pressure of $0.3 \ atm$ ? (Given: $\log 2 = 0.3010, \log 3 = 0.477$)

The adsorption of a gas on a solid surface follows the Freundlich adsorption isotherm. At $T(K)$,the gas pressure is $2 \ atm$. What is the value of $\frac{x}{m}$? (Given: $n=2$ and $k=$ constant)

The extent of adsorption of a gas on a solid depends on:

$A$ 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.