Analysis of Phosphate Salts Mixtures by a Simple Visual Alkalimetric Titration

This article discusses the issue of determining the composition of mixtures of sodium and/or potassium monobasic, dibasic and tribasic phosphate salts with the purpose of addressing, in an educational environment, intriguing features of Acid-Base chemistry. Within this context, a laboratory experiment, based on the alkalimetric titration of solutions obtained by dissolving the mixtures in an excess of strong acid, is presented and its significance is fully examined. This experiment can smoothly be integrated within first-year undergraduate general chemistry/analytical chemistry laboratory, but might as well be interpreted as a virtual experiment for classroom discussion.