Required Practical 3: Electrolysis

Test for copper(II) chloride and sodium chloride solutions

Method for both:

  • In a beaker, add 50cm3 of the solution and the place a petri dish on top of the beaker with two holes in it.

  • In the two holes, insert two carbon-graphite electrodes, without a current these will not react and are inert in the solution. Make sure the two electrodes dont touch

  • Attach crocodile clips to the tops of the electrodes, making sure a complete circuit is formed with a power pack.

  • Turn on the power pack and electrolysis starts

Effect for copper(II) chloride solution

  • Anode - Chlorine gas as halide ions are always attracted to the anode

  • Cathode - Because copper(II) is less reactive than hydrogen, copper is produced at the cathode. This is clearly shown with orange metal being formed around the electrode

Effect for sodium chloride solution

  • Anode - Chlorine gas as halide ions are always attracted to the anode

  • Cathode - Because sodium is more reactive than hydrogen, hydrogen gas is produced at the cathode