What defines a half-cell?

A half-cell is defined as a compartment containing an electrode. In electrochemical cells, which include galvanic (voltaic) cells and electrolytic cells, the half-cell specifically refers to one part of the electrochemical system where either oxidation or reduction reactions occur. In a typical setup, a half-cell consists of the electrode (which may be metal or a conductive material) and the electrolyte, which is a solution that allows ions to move and participate in the electrochemical reactions.

Understanding this concept is critical for grasping how electrochemical processes work, as each half-cell contributes to the overall behavior of the entire cell. By interacting with a counter half-cell, these components allow for the flow of electrons through an external circuit, thereby generating electrical energy. The other options do not accurately convey the fundamental aspect of a half-cell, as they either describe characteristics of a complete cell or do not encompass the integral nature of the electrode in a half-cell configuration.