Electrolysis

• Electrolysis


  Splitting up with electricity
• Electrolyte


  • A liquid or solution that can conduct electricity, e.g. an ionic compound dissolved in water or melted
• Electrode


  • A solid that is put in the electrolyte and conducts electricity
• Electrolysis


  1. Electric current passed through an electrolyte

  2. Positive ions move towards cathode (negative electrode) and gain electrons

  3. Negative ions move towards anode (positive electrode) and lose electrons

  4. Ions form uncharged elements

  5. Flow of charge created through electrolyte as ions travel to electrodes
• Electrolysis of molten ionic solids


  • Molten ionic compounds can be electrolysed because ions can move freely and conduct electricity
  • Molten ionic liquids are always broken up into their elements
  • Metal forms at cathode, non-metal forms at anode
  • Electrodes should be inert (unreactive) so they don't react with the electrolyte
• Electrolysis of molten lead bromide


  • Lead forms at cathode, bromine forms at anode
• Extracting metals from ores using electrolysis


  1. Aluminium is extracted from aluminium oxide ore

  2. Aluminium oxide has very high melting point so it's mixed with cryolite to lower melting point

  3. Positive aluminium ions attracted to negative electrode where they form aluminium atoms

  4. Negative oxygen ions attracted to positive electrode where they react to form oxygen molecules
• Metals form positive ions


  Attracted to negative electrode
• Non-metals form negative ions


  Attracted to positive electrode
• Aluminium is produced at the negative electrode
• Oxygen is produced at the positive electrode
• The role is made of graphite