Electrolytic Cells: Converting Electrical Energy into Chemical Energy
What Is an Electrolytic Cell?
Definition
Electrolytic cell
An electrolytic cell is a device that uses electrical energy to force a non-spontaneous redox reaction to occur.
It consists of three main components:
- Electrolyte: A molten or aqueous ionic compound that provides free-moving ions.
- Electrodes: A cathode (negative electrode) and an anode (positive electrode) immersed in the electrolyte.
- Power Source: A direct current (DC) power source that supplies the energy required to drive the reaction.
- External circuit:
- Provides a pathway for electrons to flow from the anode (where oxidation occurs) to the cathode (where reduction occurs).
- This flow of electrons through the external circuit generates an electric current that can be harnessed to power devices.
In an electrolytic cell:
- Reduction (gain of electrons) occurs at the cathode.
- Oxidation (loss of electrons) occurs at the anode.
The electrical energy supplied by the power source forces electrons to flow from the anode to the cathode, enabling these redox reactions.
Electrolysis of Molten Sodium Chloride
- To better understand how an electrolytic cell works, let’s analyze the electrolysis of molten sodium chloride (NaCl).
- Sodium chloride is composed of sodium (Na⁺) cations and chloride (Cl⁻) anions.
- When molten, these ions are free to move, making the compound conductive.
The Setup
- Electrolyte: Molten NaCl (l).
- Cathode: Connected to the negative terminal of the power source.
- Anode: Connected to the positive terminal of the power source.
