An Electrochemically Induced, Chemically Produced, and Mechanically Cycled Traffic-Light Effect

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 11 Issue 2 (2006) pp 98-101

An Electrochemically Induced, Chemically Produced, and Mechanically Cycled Traffic-Light Effect

Salvador Santoyo-Cázares,^†Jorge G. Ibanez,^†,‡,* Lydia Hernández-Rivera,^† Martín Adolfo García-Sánchez,^†

^†Dept. Procesos Tecnologicos e Industriales. Instituto Tecnologico y de Estudios Superiores de Occidente (ITESO), Periferico Sur Manuel Gomez Morin # 8585, Guadalajara, Jal. 45090, Mexico and Centro Mexicano de Quimica en Microescala, Depto. de ICQ, ^‡Universidad Iberoamericana, Prolongacion Reforma 880, 01210 Mexico, D.F., jorge.ibanez@uia.mx
Received September 28, 2005. Accepted December 8, 2005.

Published online: 7 March 2006

Abstract. A five-minute experiment that couples electrocoagulation with local electrochemically induced pH changes produces a red-to-green-to-red-to-green color change (i.e., a traffic-light effect). The readily available pH indicators methyl red and bromocresol green give such an effect.

Key Words: Laboratories and Demonstrations; general chemistry; physical chemistry; analytic chemistry

(*) Corresponding author. (E-mail: jorge.ibanez@uia.mx)

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