Volumetric titrations: calculating the titration percent relative error.

Abstract

The difference between the found value and the real value is known as the absolute error. When applied to a titration, the absolute error comes from the difference between the real amount of analyte present in the sample and the amount of it calculated from the titration data (namely, the titrant volume at the endpoint and the titrant molarity). In most cases, the true amount of analyte is a statistical problem. In titrations, the relative error is minimized when endpoint and stoichiometric point (both in terms of consumed volume of titrant) are very close to each other. More widely used is the percent relative error (PRE). In this exercise, a volumetric titration is carried out using a visual indicator to determine the endpoint. The analyst must stop titration just at the moment the titrated solution changes color. From the titrant volume required and data about the analyzed problem, the percent relative error should be calculated. When overtitration occurs, the error value becomes significant.