Electrolysis

• What is the aim of the electrolysis experiment described?

  To investigate what happens when aqueous solutions are electrolysed using inert electrodes.
• What equipment is needed for the electrolysis experiment?

  • 0.5 M copper(II) chloride solution
  • 0.5 M sodium chloride solution
  • Petri dish lid with bored holes
  • Two carbon rod electrodes with support bungs
  • Two crocodile/4mm plug leads
  • Low voltage power supply
  • Blue litmus paper
  • Forceps
• Why is it important that the electrodes do not touch during the experiment?

  To prevent short-circuiting and ensure proper electrolysis occurs.
• What should be done after adding the copper chloride solution to the beaker?

  Add the lid and insert electrodes through the holes.
• What voltage should the power supply be set to during the experiment?

  4V
• What is the purpose of holding the litmus paper near the positive electrode?


  To observe any color change indicating the presence of an acid.
• What should be observed at the negative electrode after turning off the power supply?

  Record observations at the electrodes.
• What are the steps to repeat the experiment with sodium chloride?

  1. Add about 50cm​3​ of sodium chloride solution to a beaker.
  2. Add the lid and insert electrodes through the holes.
  3. Attach crocodile leads to the electrode and connect to the power supply.
  4. Set the power supply to 4V and switch it on.
  5. Hold the litmus paper near the positive electrode.
  6. After a few minutes, turn off the power supply and observe the negative electrode for effervescence.
  7. Record observations at the electrodes.
• What should be observed at the negative electrode during the sodium chloride experiment?

  There should be effervescence.
• What safety precautions should be taken during the electrolysis experiment?

  • Safety goggles must be worn.
  • The room should be well ventilated due to toxic chlorine gas.
• Why must safety goggles be worn during the experiment?

  To protect the eyes from harmful substances.
• Why is it important for the room to be well ventilated during the electrolysis experiment?

  To avoid the accumulation of toxic chlorine gas.