Francesco Salvatore^1,, Maria Michela Salvatore¹

For any titration, the titration error is, by definition, the difference between the volume of titrant added to reach the end point and the volume of titrant necessary to reach a stoichiometrically defined equivalent point. A graphical approach is presented, which allows a smooth and far reaching quantitative discussion of the systematic titration error of Acid-Base titrations, on the basis of the Logarithmic Acid-Base Diagram representing the titrated solution. Considerations and relations are developed which connect this diagram to the titration error. Examples are fully developed, which show that the procedure suggested unavoidably goes beyond the technical or practical topic of evaluating the systematic titration error, and it can be especially rewarding from an educational point of view. Finally, for the reader’s convenience, algebraic expressions and brief instructions to draw Logarithmic Acid-Base Diagrams (also known as Sillén’s diagrams), by using a spreadsheet, are provided.

acid base titration, systematic error, acid base diagrams, amino acid, carbonate, bicarbonate