Introducing Electrolysis

• What should you be able to explain by the end of the video on electrolysis?

  Why ionic compounds can conduct electricity when molten or dissolved in water
• What reactions should you be able to describe during electrolysis?

  The reactions taking place at the positive and negative electrodes
• What are the two types of reactions you should be able to describe for higher tier students?

  Reduction and oxidation reactions
• What is electrolysis and why can it be tricky to understand?

  • Electrolysis is the process of using electricity to cause a chemical change.
  • It can seem tricky because it involves understanding the movement of ions and reactions at electrodes.
• What is the ionic compound mentioned in the video?

  Lead bromide
• How is lead bromide formed?

  When lead reacts with bromine
• What happens to a lead atom when lead bromide forms?

  A lead atom loses two electrons to form the lead ion $Pb^{2+}$
• What do the two bromine atoms form when they react with the electrons from lead?

  Two bromide ions $Br^{-}$
• What is the structure of a solid ionic compound like lead bromide?

  The ions are locked in a regular pattern
• Why can't solid ionic compounds conduct electricity?

  Because the ions are locked in place and not free to move
• What happens to ionic compounds when they are melted or dissolved in water?

  The forces of attraction are broken and the ions are free to move
• What are liquids or solutions that can conduct electricity called?

  Electrolytes
• What is the definition of the term "molten" in the context of ionic compounds?

  Molten means melted
• What are the two electrodes used in electrolysis called?

  The cathode and the anode
• What is the role of the cathode in electrolysis?

  It is the negative electrode that attracts positive ions
• What happens to positive lead ions at the cathode during electrolysis?

  They gain two electrons to form lead atoms
• What type of reaction occurs when lead ions gain electrons?

  Reduction reaction
• What happens to negative bromide ions at the anode during electrolysis?

  They lose one electron to form bromine atoms
• What type of reaction occurs when bromide ions lose electrons?

  Oxidation reaction
• What is the overall process of electrolysis in molten lead bromide?

  • Positive lead ions $Pb^{2+}$ move to the cathode and are reduced to lead atoms.
  • Negative bromide ions $Br^{-}$ move to the anode and are oxidized to bromine atoms.
  • Bromine atoms pair to form bromine molecules $Br_{2}$.
• What will the next video focus on regarding electrolysis?

  How to use electrolysis to extract reactive metals such as aluminium
• Where can students find more questions on electrolysis?

  In the vision workbook
• What is the significance of understanding electrolysis for higher tier students?

  It helps in describing reactions as reduction or oxidation