ELECTROLYSIS

• Electrolysis


  The decomposition of a substance by electricity
• Electrolyte


  An ionic compound, in the molten or aqueous state, that conducts electricity and is decomposed by the current

  
• Electrode


  The rods through which the direct current enters and leaves the cell
• Electrodes


  • Usually made of carbon or platinum, as they are unreactive or inert
  • Do not react with the compounds in electrolysis
• Anode


  • The electrode which is connected to the positive terminal of a cell
  • Anions are attracted to it
  • Oxidation occurs at the anode
• Cathode


  • The electrode connected to the negative terminal of the cell
  • Cations are attracted to the cathode
  • Reduction occurs at this electrode
• Electrolysis of molten electrolyte


  1. Metal (from the positive ions) is discharged at the cathode

  2. Non-metal (from the negative ions) is discharged at the anode

  
• Electrolysis of aqueous electrolyte


  1. Products come from either the electrolyte or water present

  2. Product at the cathode is a metal or hydrogen gas

  3. Product at the anode is a non-metal

  
• • Reactive metals are not discharged at the cathode
  • Instead, hydrogen from water is evolved

  
• • Sulphate and nitrate ions are not discharged at the anode
  • Instead, oxygen from water is produced