Calculations with weak protolytes: titration of acetic acid with NaOH solution.

Abstract

In this exercise, the pH value of four points in the titration of a weak acid (acetic acid) is calculated. The first point corresponds to the initial solution of the acid (no titrant was added); the second one corresponds to a substoichiometric situation (the equivalence point was not reached). The third point is the equivalence point and the last one defines a overtitration condition. Calculations are carried out in a puzzle-like expression and the results must be entered to be checked. The points are plotted in the titration curve and some hints for drawing an interactive titration graph in the case of weak protolytes are given. Two final self-evaluation exercises are proposed.