Required practical: Electrolysis

• What is the method of Electrolysis?

  - Pour the solution to be tested into a beaker

  - insert the electrodes that are connected to a DC power supply (the rods must not be touching each other)

  - Select 4V on the power supply and then switch on

  - Observe what is happening at the electrodes, you may see bubbles which tells you a gas is being made, or you may see a coating being formed around the electrode meaning that a metal is being produced

  - Use the rules to determine what is formed at the electrodes

  - We can determine if chlorine is produced by holding a piece of damp blue litmus paper above the electrodes, if it turns red and bleaches white then chlorine gas has been produced
• What is the rules at the Anode?

  if chloride, bromine or iodide there then chlorine, bromine or iodine will be formed. If not then oxygen will be made. The least reactive ion is turned into an element.
• What is the rules at the cathode?

  if the metal is very reactive then hydrogen is made. If the metal is not very reactive then the metal will be made. The least reactive ion is

  turned into an element.
• If the solution is Copper (III) chloride, what is the positive electrode (anode)?

  Chlorine
• If the solution is Copper (III) sulfate, what is the positive electrode (anode)?

  Oxygen
• If the solution is sodium chloride, what is the positive electrode (anode)?

  Chlorine
• If the solution is sodium sulfate, what is the positive electrode (anode)?


  Oxygen
• If the solution is Copper (III) chloride, what is the negative electrode (cathode)?

  Copper
• If the solution is Copper (III) sulfate, what is the negative electrode (cathode)?

  Copper
• If the solution is sodium chloride and sodium sulfate , what is the negative electrode (cathode)?

  Hydrogen