In acid-base reaction the acid gives up its proton and produces a new base.
The new base (A-) that is related to the original acid (HA) is called a conjugate base. Similarly, the original base (B-) after a accepting a proton becomes a new acid is called a conjugate acid.
Conjugate pair: The acid-base pairs associated with the loss or gain of proton is a called conjugates pair.
In any acid-base reaction, there are two conjugate acid-base pairs. For example, HA and A-, HB and B-.
A weak acid has a strong conjugate base. A weak base has a strong conjugate acid.
A strong acid has a weak conjugate base. A strong base has a weak conjugate acid.
Conjugate acid and base of H2O and HCO3-:
