QS Study

Metal-metal ion electrode in Half-Cells

A half cell is one of the two electrodes in a galvanic cell or simple battery. For example, in the Zn-Cu battery, the two half cells make an oxidizing-reducing couple.

Metal-metal ion electrode: This is the simplest type of electrode where a metal is dipped into a solution of as ions. These electrodes consist of a pure metal (M) in contact with a solution of its cation (Mn+). For example, a silver rod immersed in a solution of Ag+ ions or copper rod in copper sulphate solution. Examples are silver in silver nitrate solution, copper in copper sulphate solution. The silver-silver ion electrode is represented as, Ag│Ag+ and the copper-copper ion electrode as Cu│Cu2+.

The electrode reactions are Ag+ + e ↔ Ag and Cu2+ + 2e ↔ Cu respectively. The electrodes are reversible with respect to the metal ions.