katoder

A cathode is an electrode through which electric current leaves a polarized electrical species. It is the negative electrode in an electrolytic cell and the positive electrode in a galvanic cell or battery. The term cathode is derived from the Greek word "kathodos" meaning "descent" or "way down". In electrolysis, the cathode is where reduction occurs, meaning electrons are gained by the species being reduced. For instance, in the electrolysis of molten sodium chloride, sodium ions (Na+) migrate to the cathode and gain electrons to form neutral sodium metal (Na). In contrast, in a galvanic cell or battery, which produces electricity through spontaneous chemical reactions, the cathode is the positive electrode. Here, a reduction reaction takes place, consuming electrons and causing the positive electrode to be the site of electron gain. Understanding the cathode's role is crucial in various electrochemical applications, including electroplating, battery technology, and industrial chemical production.