Henry law constant for the solubility of methane in benzene at 298K is 4.27×10⁵ mm Hg then the solubility of methane in benzene at 298K under 760mm Hg is

Solubility of CH₄ in Benzene in mole/Kg is required

according to Henry's law,

P_A=K_H X solubility

P_A=K_H X molality

$\text{ molality =}\frac{{\mathrm{P}}_{\mathrm{A}}}{{\mathrm{K}}_{\mathrm{H}}}=\frac{760}{4.27\mathrm{X}{10}^5}=1.78\mathrm{X}{10}^{-3} \mathrm{mole} /\mathrm{kg}$