Electrolysis

• Electrolysis


  The separation of elements in insoluble ionic compounds
• Equipment for electrolysis


  • Electrodes
  • Power supply
  • Cathode
  • Anode
  • Battery
  • Wire to drive the flow of electrons
• Soluble ionic compounds


  • Lead bromide
• Solid conductors


  • Metal on carbon wire - electrons can flow between them
• Electrolyte


  Liquid or solution that is an ionic compound where ions are free to move
• Ions have to be able to move freely for electrolysis to work
• Electrolysis


  Splitting up with electricity
• Electrolysis of lead bromide solution


  1. Positive ions discharged at cathode to form pure lead

  2. Atoms oxidised at anode
• Oxidation


  Loss of electrons
• Reduction


  Gain of electrons
• Carbon can only be used to extract metals less reactive than it
• Reactivity series


  • Potassium
  • Sodium
  • Lithium
  • Calcium
  • Magnesium
  • Carbon
  • Zinc
  • Iron
  • Copper
  • Platinum
• Electrolysis only works if the ions can move
• Extracting aluminum metal from bauxite

  1. Melt Al2O3

  2. Use cryolite to lower melting point to 2000°C