Identify a pair of gases from the following that does not obey Henry's law.

Which of the following gases is least soluble in water under the same conditions of temperature and pressure?

If the $K_{H}$ values for $Ar_{(g)}$,$CO_{2_{(g)}}$,$HCHO_{(g)}$ and $CH_{4_{(g)}}$ respectively are $40.39$,$1.67$,$1.83 \times 10^{-5}$ and $0.413$,then identify the correct increasing order of their solubilities.

The statement "The mass of a gas dissolved in a given mass of a solvent at any temperature is proportional to the pressure of the gas above the solvent" is

$A$ gas '$X$' is dissolved in water at $2 \ bar$ pressure. Its mole fraction is $0.02$ in solution. The mole fraction of water when the pressure of gas is doubled at the same temperature is

If $N_2$ gas is bubbled through water at $293 \ K$, how many moles of $N_2$ gas would dissolve in $1 \ litre$ of water? Assume that $N_2$ exerts a partial pressure of $0.987 \ bar$. [Given: $K_{H}$ for $N_2$ at $293 \ K$ is $76.48 \ kbar$]