Figure 2. Primary reactions and various types of side reactions typically observed during a complexometric titration. Mez+, APCAn-, Inn-, Qn- represent, respectively, the target metal cation, the amino polycarboxylate anion, the indicator and the auxiliary ligand introduced as a component of the pH buffer. See for examples of each type of reaction

From

Understanding Complexometric Titrations of Metal Cations with Aminopolycarboxylic Acids (EDTA and Analogs) within the frame of the Notion of Reactions between Groups of Chemical Species

Maria Michela SALVATORE, Francesco SALVATORE

World Journal of Chemical Education. 2015, 3(1), 5-21 doi:10.12691/wjce-3-1-2