reference electrode

A reference electrode is a type of electrode used in electrochemical measurements. It provides a stable and known electrical potential against which other electrodes can be measured. A common example is the calomel electrode, which is composed of mercury, calomel (mercurous chloride), and a potassium chloride solution.12

In a pH meter, for instance, a reference electrode works in conjunction with a pH-responsive electrode (often made of glass) to measure the hydrogen-ion activity in a solution. The voltmeter then measures the potential difference between these two electrodes. Electrochemical processes, including those involving electrodes, are vital in analytical chemistry and are increasingly used as environmentally friendly alternatives to traditional chemical methods.13