electrolysis

• key terms and definitions:

  • When an electric current is passed through a molten ionic compound the compound decomposes or breaks down
  • The process also occurs for aqueous solutions of ionic compounds
  • Liquids and solutions that are able to conduct electricity are called electrolytes
  • Covalent compounds cannot conduct electricity hence they do not undergo electrolysis
• key terms and definitions

  • An electrolytic cell is the name given to the set-up used in electrolysis and which consists of the following:
  • Electrode: a rod of metal or graphite through which an electric current flows into or out of an electrolyte
  • Electrolyte: ionic compound in molten or dissolved solution that conducts the electricity
  • Anode: the positive electrode of an electrolysis cell
  • Anion: negatively charged ion which is attracted to the anode
  • Cathode: the negative electrode of an electrolysis cell
  • Cation: positively charged ion which is attracted to the cathode
• PANIC:


  PANIC -Positive (is) Anode Negative Is Cathode.
• electrical conductivity of ionic compounds:

  • Ionic compounds in the solid state cannot conduct electricity since they have no free ions that can move and carry the charge
  • The ions must be able to move and can only do so in the molten state or when dissolved in a solution, usually aqueous
  • When the cell is turned on and an electric current is passed through an electrolyte the ions in the solution start to move towards the electrodes
• movement of ions:

  • During electrolysis the electrons move from the power supply towards the cathode
  • Electron flow in electrochemistry thus occurs in alphabetical order as electrons flow from the anode to the cathode
  • Positive ions within the electrolyte migrate towards the negatively charged electrode which is the cathode
  • Negative ions within the electrolyte migrate towards the positively charged electrode which is the anode
• Electrolysis

  1. Electric current passed through molten ionic compound

  2. Compound decomposes

  3. Also occurs for aqueous (water) solutions of ionic compounds
• Electrolytes

  Liquids and solutions that are able to conduct electricity
• Covalent compounds

  Cannot conduct electricity hence they do not undergo electrolysis
• Electrolytic cell

  Set-up used in electrolysis
• Components of an electrolytic cell

  • Electrode: an electrical conductor that is used to make contact with a non-metallic part of a circuit. electrodes are solid conductors either carbon or metal
  • Electrolyte: ionic compound in molten or dissolved solution that conducts electricity
  • Anode: positive electrode
  • Anion: negatively charged ion attracted to anode
  • Cathode: negative electrode
  • Cation: positively charged ion attracted to cathode
• electrolysis


  breaking something up with electricity. we need electrolysis because we perform it to extract reactive metals from their ores