A molecular entity capable of donating a hydron (proton) to a base, (i.e. a
'hydron donor') or the corresponding chemical species. For example:
H2O,
H3O+,
CH3CO2H,
H2SO4,
HSO4−,
HCl,
CH3OH,
NH3.
See also: conjugate acid–base pair
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1091 (https://doi.org/10.1351/pac199466051077)