Light-emitting bipolar electrochemistry: a straightforward way to illustrate thermodynamic aspects to students.

Thermodynamics is one of the most fascinating parts of physical chemistry, involved in different natural phenomena. In particular, the spontaneity or non-spontaneity of a chemical reaction is directly linked to fundamental thermodynamic parameters such as the Gibbs free energy change. Commonly this can be easily correlated with the electric work produced or required during an electrochemical reaction. In this context, the direct visualization of the electromotive force facilitates the student's understanding of the fundamental concepts behind the spontaneity of coupled reactions. Herein, we take advantage of the concepts of endogenous and exogenous bipolar electrochemistry to develop an easy and straightforward approach for the introduction of the thermodynamic concept of spontaneity to undergraduate students. In such a wireless electrochemical approach, the chemical information of two coupled reactions is encoded by the light emission of a light-emitting diode employed as bipolar electrode. This results in a direct optical readout of thermodynamic information of the involved redox reactions. [ABSTRACT FROM AUTHOR]