When an acid and a base react, the products are a new acid and base. For example,
the acetate ion, CH3COO–, in reaction 6.7 is a base that reacts with the acidic
ammonium ion, NH4
+, to produce acetic acid and ammonia. We call the acetate ion
the conjugate base of acetic acid, and the ammonium ion is the conjugate acid of
ammonia.