Normality can be used for acid-base titrations. For example, sulfuric acid (HSO) is a diprotic acid. Since only 0.5 mol of HSO are needed to neutralize 1 mol of OH, the equivalence factor is:
:f(HSO) = 0.5
If the concentration of a sulfuric acid solution is c(HSO) = 1 mol/L, then its normality is 2 N. It can also be called a "2 normal" solution.
Similarly, for a solution with c(HPO) = 1 mol/L, the normality is 3 N because phosphoric acid contains 3 acidic H atoms.