Electrolysis

• Electrolysis

  Breaks down a substance using electricity
• Ionic compounds

  • Can only be electrolysed when they are molten or in water
  • Their ions are then free to move around and carry their charge to the electrodes
• Electrolysis

  1. Positive ions move to cathode (negative electrode)

  2. Negative ions move to anode (positive electrode)
• At the negative electrode (cathode)

  Positive ions gain electrons (so are reduced)
• At the positive electrode (anode)

  Negative ions lose their extra electrons (So are oxidised)
• Less reactive substance

  Produced at cathode (negative electrode)
• Oxygen & water given off from discharged hydroxide ions in aqueous solution
• A halogen produced if the electrolyte is a solution of halide
• Carbon anodes need to be replaced frequently because oxide ions are discharged as oxygen at anodes producing carbon dioxide which wears away anodes
• Sodium Chloride solution —electrolysis—>

  Hydrogen gas + chlorine gas + sodium hydroxide solution