1) The process of electrolysis

• Electrolysis is the use of an electrical current to break down compounds containing ions into their constituent elements
• The substance being broken down is called the electrolyte.
• The electrodes are made from solids that conduct electricity.
• During electrolysis:

  Aqueous solution, e.g. sodium chloride solution

  -negatively charged ions move to the anode (positive electrode) -positively charged ions move to the cathode (negative electrode
• Electrolysis can be used to separate ionic compounds into elements.
• For example, lead bromide can be split into lead and bromine:

  • The lead bromide is heated until it melts.
  • The positively charged lead ions move to the negative electrode (cathode).
  • Here they gain electrons to form lead atoms - pure lead is produced at this electrode.
  • The negatively charged bromide ions move to the positive electrode (anode).
  • Here they lose electrons to form bromine atoms, which join together to form bromine molecules-bromine is released at this electrode.
• At the cathode: Pb2+ + 2e → Pb

  At the anode: 2Br -> Br2+ 2e-
• lonic substances can only conduct electricity when they are molten or dissolved in water.