This practical involves simple copper electroplating. This simplified version of the copper plating practical does not require copper sulphate solution and can be conducted as part of a science club or introduction into ionisation or metals.
Equipment typically required (per set):
- 500ml beaker
- Large iron nail (silver colour)
- 1m insulated copper wire
- Labpack or 6V power source
- 60g sodium chloride (table salt)
- Wire strippers
- Vinegar
- Strip of copper foil (100mmx40mm approx)
- 2x crocodile clips
The vinegar is poured into the beaker to a level which is enough to submerge the nail. The salt is added and stirred until dissolved. The copper strip is bent so that it rests on the edge of the beaker but is mostly submerged in the vinegar. A length of insulated wire is connected to the top of this strip using a crocodile clip and the other end connected to the power source D.C terminal.
Another length of insulated wire is partially coiled around the top of the nail so that it is secure and the other end connected to the other supply terminal.
Ensure that both the nail and the copper strip are partially submerged in the vinegar but not touching before turning on the power supply. The labpack should be set at around 6V D.C.
After about 30 minutes you should start to see the nail change to a copper colour. If left for about an hour, the nail should be sufficiently copper plated to see the full effect. You will notice that the copper strip has become brittle or flaky during this time. This is because the process literally takes copper from here and deposits it on the nail.
In this setup, when the current flows, one metal loses electrons while the other gains electrons. The two different metals used in this practical lose electrons differently. In this case the copper is more likely to lose electrons than the iron nail. The more active metal of the two (in this case the copper foil) is the anode. The other is the cathode.
As the copper strip loses electrons, copper ions are formed. This process is called ionisation. These ions are dissolved into the electrolyte (the salt/vinegar solution).
At the cathode (the nail), positively charged ions gain electrons. Because the metal in the nail is not getting ionised, the only metal ions available to gain electrons are the copper ions in the solution. As the copper ions gain electrons, they become copper atoms and these are deposited onto the iron nail. Over time, a layer of this copper will plate the cathode (nail).