Electroplating (Cambridge (CIE) IGCSE Chemistry)
Revision Note
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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
Examiner Tip
Extended Tier students may be asked to write the ionic half equations for the reaction at each electrode. For the example above, these would be:
At the anode: Sn (s) → Sn2+ (aq) + 2e-
At the cathode: Sn2+ (aq) + 2e- → Sn (s)
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
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