Understanding the Nernst equation and other electrochemical concepts: An easy experimental approach for students

Abstract

The goal of the present laboratory experiment is to deepen the understanding of the Nernst equation and some other concepts that are essential in electrochemistry. In this practical laboratory session, students first learn that the equilibrium potential of an electrode is related to the difference between two equilibrium inner electric potentials (also called Galvani potentials), namely, φ M (inner electric potential of the metallic phase) and φ sol (inner electric potential of the solution phase). Second, the concept of overvoltage is defined and the method to measure it is described. Finally, it is shown how and why the inner potential of a solution changes with the distance to the working electrode when a current flows through the solution and how the potential difference is distributed in an electrochemical cell when a current is flowing through it. © 2012 The American Chemical Society and Division of Chemical Education, Inc.