Electrochemical reactions are vital to many processes in technology and the human body and involve the transfer of electrons from one chemical species to another. These reactions are called reduction-oxidation reactions or redox reactions.
When a species loses electrons, it undergoes oxidation, and we say that it is oxidized. When a species gains electrons, it has undergone reduction, and we say that it is reduced. In an electrochemical galvanic cell, redox reactions occur spontaneously, which generate electrical energy. However, in an electrolytic cell, electrical energy is applied, which causes the redox reactions to occur.
An electrolytic cell consists of the reaction solution called the electrolyte, which contains any chemical species that are oxidized or reduced as well as ions needed to enable electron flow. The electrolytic cell has two metal electrodes that are immersed in the electrolytic solution. An external circuit connects the two electrodes, which completes the circuit and enables us to apply voltage or current.
The applied current or voltage is what causes the electrochemical reaction to take place. The oxidation half-reaction occurs at the anode, and the reduction h