Amount fraction
\(x\) of a species in the liquid phase divided by the partial pressure
\(p\) of that species in the gas phase under equilibrium conditions at infinite dilution:
\[H_{\rm{s}}^{xp}: = \underset{x \to 0}{\rm{lim}}\frac{x}{p}\]Note:
The coherent SI unit for \(H_{\rm{s}}^{xp}\) is \(\pu{Pa-1}\).
Example:
The Henry solubility (defined via liquid-phase amount fraction and partial pressure) of ozone in water at \(T = \pu{298.15 K}\) is \(H_{\rm{s}}^{xp}(\ce{O3}) = \pu{1.8E-9 Pa-1}\).
See also: Henry’s law solubility constant
Source:
PAC, 2022, 94, 71. 'Henry’s law constants (IUPAC Recommendations 2021)' on page 75 (https://doi.org/10.1515/pac-2020-0302)