A Simple Hydrogen Electrode

摘要

The construction of an inexpensive, robust, and simple hy-drogen electrode, as well as the use of this electrode to measure"standard" potentials, is described. Calculating and measuringelectromotive force, EMF, of galvanic cells is central to mostgeneral chemistry curricula. To calculate cell potentials, studentsuse a standard reduction reference scale. This scale is based onthe standard hydrogen electrode, a hypothetical electrode withexact concentrations and ideal behavior (1-3). The normalhydrogen electrode is described in many textbooks and articles,but is both inconvenient and expensive (4). Instead of measur-ing standard reduction potentials directly, secondary referenceelectrodes such as calomel or silver—silver chloride electrodes arecommonly used. Various secondary electrodes can be found inthe literature, (5-7). Hydrogen electrodes are also reported, (8,9), but to my knowledge, no "home-made" hydrogen electrodefor direct measurements of potentials has been reported previ-ously. Hydrogen often acts as a reducing agent, thus the electrodedescribed here is closed to avoid hydrogen gas reacting with thesubstances that are to be measured.