Term: conjugate acid–base pair
https://doi.org/10.1351/goldbook.C01266

Definition:
The Brønsted acid BH+ formed on protonation of a base B is called the conjugate acid of B, and B is the conjugate base of BH+. (The conjugate acid always carries one unit of positive charge more than the base, but the absolute charges of the species are immaterial to the definition.) For example: the Brønsted acid HCl and its conjugate base Cl− constitute a conjugate acid–base pair.

Related Terms:
1) brønsted acid (http://doi.org/10.1351/goldbook.B00744).

Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1099 (https://doi.org/10.1351/pac199466051077)

Citation: 'conjugate acid–base pair' 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.C01266

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