Term: electrolytic hygrometer
https://doi.org/10.1351/goldbook.E01972

Definition:
hygrometer using a hygroscopic substance (for example, diphosphorus pentaoxide, P2O5) which is transformed into an electrolyte (phosphoric acid, H3PO4) in contact with the moisture in the gas. The electrolyte (phosphoric acid) is electrolysed continuously and the electrolysis current is measured. At a constant flow of the gas to be analysed, the electrolysis current is a linear function of the water concentration.

Related Terms:
1) hygrometer (http://doi.org/10.1351/goldbook.H02914).

Source: PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2195 (https://doi.org/10.1351/pac199062112167)

Citation: 'electrolytic hygrometer' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.E01972

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