Electrolysis

• What is the process of electrolysis used for?


  To cause a chemical reaction using an electrical current
• What does the term 'electrolysis' mean?


  'Splitting up with electricity'
• What is an electrolyte?


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


  A solid that conducts electricity and is submerged in the electrolyte
• Which direction do positive ions move during electrolysis?


  Towards the cathode
• What happens to positive ions at the cathode?


  They gain electrons and are reduced
• Which direction do negative ions move during electrolysis?


  Towards the anode
• What happens to negative ions at the anode?


  They lose electrons and are oxidized
• What is created as ions gain or lose electrons during electrolysis?


  The uncharged element is formed and discharged from the electrolyte
• Why can't an ionic solid be electrolyzed?


  • Ions are in fixed positions
  • Ions cannot move
  • No electrical conductivity
• Why can molten ionic compounds be electrolyzed?


  Because the ions can move freely and conduct electricity
• What happens to molten ionic liquids during electrolysis?


  They are always broken up into their elements
• What occurs to positive metal ions at the cathode during electrolysis?


  They are reduced to the element
• What occurs to negative non-metal ions at the anode during electrolysis?


  They are oxidized to the element
• What is the equation for the reduction of lead ions during electrolysis?

  $Pb^{2+} +$$2e^{-} \rightarrow Pb$
• What is the equation for the oxidation of bromide ions during electrolysis?


  $2Br^{-} \rightarrow Br_{2} +$$2e^{-}$
• When is electrolysis used to extract metals?


  • When metals are too reactive to be reduced with carbon
  • When metals react with carbon
  • To extract metals from their ores
• What is the ore from which aluminium is extracted?

  Bauxite
• What is aluminium oxide's chemical formula?


  $Al_{2}O_{3}$
• Why is cryolite mixed with aluminium oxide during extraction?


  To lower the melting point of aluminium oxide
• What does the molten mixture of aluminium oxide and cryolite contain?


  Free ions that conduct electricity
• What happens to positive Al$^{3+}$ ions at the negative electrode?


  They gain three electrons and are reduced to aluminium
• What happens to negative O$^{2-}$ ions at the positive electrode?


  They lose two electrons and are oxidized to oxygen
• What is produced at the positive electrode during electrolysis of aluminium oxide?


  Oxygen
• What is the overall equation for the electrolysis of aluminium oxide?


  $2Al_{2}O_{3} \rightarrow 4Al +$$3O_{2}$
• Why does the anode need to be replaced regularly during electrolysis?


  Because it reacts with oxygen to produce carbon dioxide
• What is the simplified reaction for the electrolysis of aluminium oxide?


  • Aluminium oxide → Aluminium + Oxygen
  • $2Al_{2}O_{3} \rightarrow 4Al +$$3O_{2}$
• What is the byproduct of the electrolysis of aluminium oxide?


  Oxygen
• What happens to the neutral oxygen atoms produced during electrolysis?


  They combine to form O$_{2}$ molecules
• What is the significance of the flow of charge through the electrolyte?


  It allows the ions to travel to the electrodes
• How does the process of electrolysis contribute to metal extraction?


  It allows for the reduction of metal ions to their elemental form
• What role do inert electrodes play in the electrolysis process?


  They do not react with the electrolyte
• What is the main energy requirement for electrolysis?


  To melt the ore and produce the required current
• What state of matter is involved in electrolysis?


  Solid
• What is the purpose of a battery in electrolysis?


  It conducts electricity
• What is required for electrolysis to occur?


  A liquid or solution that contains ions
• What equipment is needed for electrolysis?


  Beaker, electrolyte, and ionic compound
• What role do wires play in electrolysis?


  They allow electrons to flow
• What happens to ions during electrolysis?


  They are free to move
• What is the cathode in electrolysis?


  The electrode where positive ions are discharged