Introduction
Electrolysis is widely used in industry for metal extraction, purification, electroplating, and production of important chemicals. These applications demonstrate how chemical principles are used in real-world manufacturing and energy systems.

1. Extraction of Aluminium – Hall-Héroult Process

• Electrolyte: Molten aluminium oxide (Al₂O₃) dissolved in cryolite

• Electrodes: Graphite (inert)

• Cathode Reaction:
  Al³⁺ + 3e⁻ → Al

• Anode Reaction:
  C + O²⁻ → CO₂ + 4e⁻
  ✅ Pure molten aluminium is collected at the cathode.

2. Electrolytic Refining of Copper

• Anode: Impure copper

• Cathode: Pure copper plate

• Electrolyte: Acidified CuSO₄

• Anode Reaction:
  Cu → Cu²⁺ + 2e⁻

• Cathode Reaction:
  Cu²⁺ + 2e⁻ → Cu
  ✅ Pure copper plates at the cathode; impurities fall off as anode mud.

3. Electroplating (e.g., Silver Plating a Spoon)

• Anode: Silver rod

• Cathode: Metal spoon

• Electrolyte: AgNO₃ solution

• Cathode Reaction:
  Ag⁺ + e⁻ → Ag
  ✅ A shiny silver layer forms on the spoon for protection or beauty.

4. Electrolysis of Brine (Aqueous NaCl)

• Electrolyte: Brine solution

• Electrodes: Inert

• Cathode Reaction:
  2H₂O + 2e⁻ → H₂ + 2OH⁻

• Anode Reaction:
  2Cl⁻ → Cl₂ + 2e⁻
  ✅ Products: Hydrogen gas (H₂), Chlorine gas (Cl₂), and NaOH in solution.

5. Electrolysis of Water (Hydrogen Fuel Production)

• Electrolyte: Acidified water (dilute H₂SO₄)

• Cathode Reaction:
  2H⁺ + 2e⁻ → H₂

• Anode Reaction:
  2H₂O → O₂ + 4H⁺ + 4e⁻
  ✅ Produces hydrogen gas for fuel and oxygen gas.

Summary Table

NECTA-Style Question
Q: State three industrial applications of electrolysis and write balanced equations for each.

A:

1. Extraction of Al:
   Al³⁺ + 3e⁻ → Al

2. Copper Refining:
   Cu → Cu²⁺ + 2e⁻ ; Cu²⁺ + 2e⁻ → Cu

3. Brine Electrolysis:
   2Cl⁻ → Cl₂ + 2e⁻ ; 2H₂O + 2e⁻ → H₂ + 2OH⁻

Real-Life Use Cases

• Production of metals (Al, Na, Mg)

• Jewelry and utensil electroplating

• Chlorine and NaOH production

• Green hydrogen fuel generation