If we titrate the weak acid HB with a base, there will be a point in the titration at
which the number of moles of base added is half the number of moles of acid
initially presents.From the resultant titration curve we obtain the ionization constant, as
explained in the following paragraph.From the titration curve shown in Figure 4.1, we see at the point denoted as half
equivalence point, where [HB] = [B?], the pH is 4.3.