Electroplating (Cambridge (CIE) IGCSE Chemistry)

Electroplating

What is electroplating?

• Electroplating is a process where the surface of one metal is coated with a layer of a different metal

• The cathode / negative electrode is the object to be electroplated

• The anode / positive electrode is made from the pure metal that will be plated onto the object 

• The electrolyte is an aqueous solution of a soluble salt of the pure metal at the anode

Electroplating a strip of iron with tin

A piece of iron being electroplated with tin. The electrolyte is tin(II) chloride, a water-soluble salt of tin

• At the anode:

  • Tin atoms lose electrons to form tin ions in solution

  • The loss of electrons is oxidation

• At the cathode:

  • Tin ions gain electrons to form tin atoms

  • The gain of electrons is reduction

  • The tin atoms are deposited on the strip of iron metal, coating it with a layer of tin

What is electroplating used for?

• Electroplating is done to make metals more resistant to corrosion or damage

  • e.g. chromium and nickel plating

  • e.g. galvanising - zinc plating / coating, typically done to iron and steel

• It is also done to improve the appearance of metals,

  • e.g. coating cutlery and jewellery with silver