The idea of in situ generation of known amounts of chemical reagents is an intriguing one that has occupied the attention of many chemists. Electrochemists, in particular, have been notably successful in this regard. The basis for this is, of course, Faraday’s law of electrolysis, which states that the quantity of electricity passed (coulombs) is directly proportional to the amount of chemical reaction (equivalents) that takes place at an electrode. As we have seen in Chapter 3, a mathematical expression for this concept is readily apparent: