Electroplating
The use of electrolysis to coat an object with a thin layer of metal, for corrosion resistance, appearance, or wear resistance.
Electroplating Setup
| Component | What to Use | Why |
|---|---|---|
| Cathode (-) | Object to be plated | Metal ions are reduced onto its surface |
| Anode (+) | Pure plating metal | Dissolves to replenish metal ions in solution |
| Electrolyte | Solution of plating metal salt | Provides the metal ions (e.g., CuSO₄ for copper plating) |
Applications of Electrolysis
| Application | Details |
|---|---|
| Electroplating | Chromium/nickel plating of cutlery, taps, jewellery |
| Aluminium extraction | Hall-Heroult process: electrolysis of Al₂O₃ in molten cryolite |
| Chlor-alkali industry | Electrolysis of brine producing Cl₂, H₂, and NaOH |
| Copper purification | Impure Cu anode dissolves; pure Cu deposited at cathode |
📋 Exam Tip
In electroplating, the object to be plated is always the cathode. Remember: the plating metal is reduced onto the cathode surface (PANIC: Positive Anode, Negative Is Cathode).