Stoichiometric approach to redox back titrations in ethanol analyses

Abstract

This article refers to calculations involved with determination of ethanol, analyzed according to redox back titration principle. A quantitative reasoning, based on logical sequence of statements, is presented for derivation of the formulas required to calculate the results of chemical analyses according to stoichiometric principles. The titrations are considered as two-step analytical procedures. This way, one can gain an insight into a classical redox titration and get a knowledge on the advantages of back titrations. How to cite this article: Michałowska-Kaczmarczyk AM, Michałowski T. Stoichiometric approach to redox back titrations in ethanol analyses. Ann Adv Chem. 2019; 3: 001-006. https://doi. The literature designed for analytical laboratory purposes provides more or less detailed description of analytical methods. The description of quantitative nature is often preceded by preliminary information on the analytics. However, the question of the calculation of the results of analysis is commonly presented in the form of a ready formula, into which the data obtained from the experiments are inserted. The knowledge on the derivation of the related formula, based on stoichiometric reaction notations, is then presented as a "dry" information, for assimilation and memorization. This approach can be justiiied in the case of simple analyses. It is debatable, however, whether the same approach should be applied to more complex analytical procedures. This paper concerns calculations involved with determination of ethanol contents, taken as interesting examples of classical, titrimetric analysis. Importance of classical determination of this analyte is revealed by the facts that: (1) a variety of analytical procedures were suggested for the ethanol determination [1-11]; (2) the international ethanol reference solution is prepared by the dichromate oxidation method [12].