Basic & Molten Compounds

• What does electrolysis mean?

  Breaking something apart using electricity. It is a process used to separate a compound into its elements.
• What is an electrolyte?

  A liquid or solution that conducts electricity
• What is an electrode?

  A solid that conducts electricity and is submerged into the electrolyte
• Why is electrolysis not used to extract all metals?

  Electrolysis is very expensive (due to requiring lots of electricity)
• What happens to positive ions during electrolysis?

  1. They are attracted to the cathode
  2. They gain electrons
  3. This means they have been reduced
• What happens to negative ions during electrolysis?

  1. They move towards the anode (positive electrode)
  2. They lose electrons
  3. This means they have been oxidised
• Why can’t ionic solids be electrolysed?

  The ions are in fixed positions- they can’t move and carry charge
• Why can molten ionic compounds be electrolysed?

  The ions can move freely when the ionic compound is molten and thus they can conduct electricity
• Why should the electrodes be inert during electrolysis?

  So that they don’t react with the electrolyte and dissolve away, requiring replacement
• How does electrolysis work?

  1. An electric current is passed through the electrolyte causing ions to move to the electrodes
  2. Positively charged ions moves to the cathode
  3. Negatively charged ions move to the anode
  4. Ions are discharged at the electrodes, producing elements
• In the electrolysis of molten lead bromine (PbBr2) which 2 ions would be present?

  Pb2+ and Br-
• In the electrolysis of molten lead bromine (PbBr2), what would form at the positive electrode (anode)?


  Bromine gas: Br2
• In the electrolysis of molten lead bromine (PbBr2), what would form at the negative electrode (cathode)?


  Molten lead :Pb
• In the electrolysis of molten lead bromine (PbBr₂), what would be the half equation for the reaction at the positive electrode (anode)?

  2Br⁻ —> Br₂ + 2e⁻
• In the electrolysis of molten lead bromine (PbBr2), what would be the half equation for the reaction at the negative electrode (cathode)?

  Pb²⁺ + 2e⁻ —> Pb