A conjugate acid is formed when a base gains a proton (H+ ion) during a chemical reaction. It is the species that remains after a base has accepted a proton in the context of the Brønsted–Lowry acid-base theory.
The species that remains after an acid donates a proton during a chemical reaction.
Brønsted–Lowry Acid: An entity capable of donating a proton (H+) to another species.
The process of adding a proton to an atom, molecule, or ion