An electrolytic cell is a type of electrochemical cell that uses electrical energy to force a non-spontaneous chemical reaction to occur. It is the opposite of a galvanic (voltaic) cell. Electrolytic cells are essential in IB Chemistry Topic 9 (Redox Processes) and Topic 19 (HL), particularly in the contexts of electroplating, metal extraction, and electrolysis of molten or aqueous ionic compounds. Understanding electrolytic cells strengthens your knowledge of electron flow, electrode roles, and redox behavior.
What Is an Electrolytic Cell?
An electrolytic cell is a system that uses an external power source to drive a chemical reaction that would not occur on its own.
Key features:
- Electrical energy → chemical change
- Requires a power supply (battery/DC source)
- Redox reactions are forced
- Electrons are pushed in the opposite direction compared to a galvanic cell
Electrolytic cells are widely used in industry to produce chemicals, extract metals, and refine materials.
How an Electrolytic Cell Works
An electrolytic cell contains:
- Two electrodes (anode and cathode)
- An ionic substance (molten or aqueous)
- A power source to force electron movement
1. Power supply forces electron flow
Electrons are pushed from the positive terminal toward the negative terminal.
2. Oxidation occurs at the anode
Anode is positive in an electrolytic cell because it attracts anions.
3. Reduction occurs at the cathode
Cathode is negative because it supplies electrons.
Even though electrode signs change, oxidation always occurs at the anode and reduction always at the cathode.
