Some studies on the determination of indicator transition and its use in the titration of weak basic samples

Abstract

In the titration of a weak basic sample, especially in the dilute solution, the transition color of the indicator is not sharp at the equivalence point. In order to avoid the indicator error, the color transition near the equivalence point must be known accurately. The color transition of an acid-base indicator can be calculated from complementary tristimulus data. To ensure accuracy, however, the chemical stoichiometric relationships about the acid-base equilibria are considered. A general expression for determination of the equivalence point is presented and factors influencing the titration are discussed.