Knowra Conjugate acid–base pair Conjugate acid–base pair A conjugate acid–base pair consists of two species that differ by one proton. The acid donates that proton to become its conjugate base; the base accepts it to become its conjugate acid.
Brønsted–Lowry acid–base theory : An acid–base theory defining acids as proton donors and bases as proton acceptors. It supplies the proton-transfer definition that makes conjugate pairs possible.
Proton : A positively charged subatomic particle found in atomic nuclei; in chemistry, H⁺ denotes a proton transferred between species. The one-proton difference is the defining feature of a conjugate pair.
Buffer solution : A solution that resists pH change through equilibria involving a weak acid and its conjugate base, or a weak base and its conjugate acid. A buffer works by allowing its conjugate members to consume added acid or base.
Salt : An ionic compound composed of cations and anions, often formed in acid–base neutralization. A salt may contain conjugate ions, but the compound itself is not a conjugate pair.
Proton transfer : The movement of a proton from one chemical species to another. This is the reaction step connecting the two members of a conjugate pair.
Chemical species : A chemically distinct atom, molecule, ion, or other identifiable entity. Each member of a conjugate pair is a distinct chemical species.
Henderson–Hasselbalch equation : An equation relating solution pH to an acid's pKa and the ratio of conjugate base to acid concentrations. It estimates pH directly from the proportions of a conjugate pair.
Neutralization reaction : An acid–base reaction in which acidic and basic species react, often producing water and a salt. Neutralization is a reaction class; a conjugate pair is a relationship between two species.
Amphoteric substance : A substance that can act as either an acid or a base, depending on its reaction partner. Water and other amphoteric species can form different conjugate pairs in different reactions.
Chemical equilibrium : A state in which forward and reverse reaction rates are equal, leaving concentrations constant. Conjugate acid–base forms coexist at equilibrium in reversible proton-transfer reactions.
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