At 298K temperature ,the Henry constants for $Ar,CO_2,CH_4$ and $O_2$ are 40 kbar,1.6 kbar,0.41 kbar and 34 kbar respectively.Which of the following show maximum solubility in water at a given pressure?

Question

$\begin{array}{1 1}(a)\;CH_4\\(b)\;CO_2\\(c)\;Ar\\(d)\;O_2\end{array}$

Answer 1

Answer: $CH_4$

The dissolution of a gas in a liquid is governed by Henry’s law, according to which, at a given temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas.

The inverse of the Henry's law constant, multiplied by the partial pressure of the gas above the solution, is the molar solubility of the gas, $\rightarrow $ Solubility $\propto \large\frac{1}{\text{Henry's Constant}}$

Since $CH_4$ has the lowest Henry's Law constant, it has the highest solubility.