Title: dimensionless Henry’s law volatility constant
Long Title: IUPAC Gold Book - dimensionless Henry’s law volatility constant
DOI: 10.1351/goldbook.09019
Status: current

Definition
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 \(H_{\rm{v}}^{cc}(\ce{O3}) = 4.0\).

Related Term
- Henry’s law volatility constant: https://goldbook.iupac.org//terms/view/09022

Source
- PAC, 2022, 94, 71. 'Henry’s law constants (IUPAC Recommendations 2021)' on page 74 (https://doi.org/10.1515/pac-2020-0302)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09019/html
- json: https://goldbook.iupac.org/terms/view/09019/json
- xml: https://goldbook.iupac.org/terms/view/09019/xml

Citation: Citation: 'dimensionless Henry’s law volatility constant' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09019
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Accessed: 2026-06-12T17:50:46+00:00