Electroplating

Electroplating is another example of the use of an electrolytic cell.

In this particular case (example 6 from your workbook), an electrolytic cell is being used to silverplate a spoon (or at least the bottom half of the spoon since that is all that is in the solution). The power supply in this case is forcing electrons from the left to the right. The electrons go into the electrolytic cell onto the spoon. The presence of electrons on the spoon will cause the silver ions to plate onto the spoon as silver metal. We call this electrode the cathode because this is where reduction is taking place. The half-reaction is Ag⁺ + e^- Ag. At the other electrode, the anode, oxidation is taking place and something is giving up electrons. For good electroplating it should be silver, because if it is not silver then different ions would mix into the solution as that particular metal is oxidized. When that happens, those metal ions will plate onto the spoon as well as the silver. Notice the overall reaction is that silver becomes silver. The only real change is where the silver is. It has been moved from the silver bar on the left to the spoon on the right.
	Anode oxidation Ag Ag⁺ + e^-	Cathode reduction Ag⁺ + e^- Ag
	Overall reaction Ag Ag⁺ + e^- Ag or Ag Ag

Practice

Now use the diagram in exercise 3 in your workbook to show how you could go about copper plating a fork. Refer back to example above (example 6 in your workbook) if you need to. When you are done, check your answers below or discuss your diagram with an instructor to make sure you have included all the necessary components.

Electroplating is a very important industrial process. Again, if you happen to know or meet someone who works in any of the local tool or metal processing companies, you might ask them if they can tell you about some of the coatings that go onto various tools and the steps that have to be followed to make the process work.

Answers

If the power supply forces electrons to the left, the cathode will be on the left as shown here. If you chose to force the electrons to the right, the position of the electrodes and reactions will be opposite what is shown here.
The solution should contain copper ions and some type of anion. The fork to be plated should be the cathode. The anode should be made of copper.
cathode reduction Cu²⁺ + 2 e^- Cu	anode oxidation Cu Cu²⁺ + 2 e^-

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