Methyl red: A chameleon that reveals the partition between two phases as a function of pH. An extraction experiment

M. JAZMÍN SILVERO,; FABIO E. MALANCA; CÉSAR GÓMEZ; JUAN FRAIRE; GERARDO A. ARGÜELLO

The Chemical Educator

Año: 2012 vol. 17 p. 163 - 163

A picture is worth a thousand words,” and besides it is easier to remember. This work is based on that premise, and its main objective is to show that creating a strong visual impact on the student’s mind is a useful tool to teach important chemistry concepts. The activities proposed involve a biphasic medium composed of an aqueous solution at different pH levels and petroleum ether (60–80°C), where an acid-basic indicator such as methyl red is employed to examine the phenomenon occurring in each phase, as it changes its color like a “chameleon.” During the process, students are introduced to core concepts of physical chemistry through a solvent partition system. The experiment is suitable for both qualitative and quantitative analyses of the extraction process.