Amount concentration
\(c_{\rm{g}}\) of a species in the gas phase divided by the amount concentration
\(c_{\rm{g}}\) of that species in the liquid phase under equilibrium conditions at infinite dilution:
\[H_{\rm{v}}^{cc}: = \underset{c_{\rm{l}} \to 0}{\rm{lim}}\frac{c_{\rm{g}}}{c_{\rm{l}}}\]Note:
Instead of the amount concentrations \(c_{\rm{g}}\) and \(c_{\rm{l}}\), the mass concentrations \(\gamma_{\rm{g}}\) and \(\gamma_{\rm{l}}\) can be used here. This yields the same dimensionless Henry volatility because the molar mass \(M\) of the solute cancels out: \(\gamma_{\rm{g}}/\gamma_{\rm{l}} = (c_{\rm{g}}M)/(c_{\rm{l}}M) = c_{\rm{g}}/c_{\rm{l}}\).
Example:
The dimensionless Henry volatility of ozone in water at \(T = \pu{298.15 K}\) is \(H_{\rm{v}}^{cc}(\ce{O3}) = 4.0\).
See: Henry’s law volatility constant
Source:
PAC, 2022, 94, 71. 'Henry’s law constants (IUPAC Recommendations 2021)' on page 74 (https://doi.org/10.1515/pac-2020-0302)