Electroplating

This lesson covers:

  1. The process of electroplating
  2. The reasons why some metal objects are electroplated

What is electroplating?


Electroplating uses the principles of electrolysis to cover materials with a layer of metal

Example 1 - Improving the appearance of metals

Illustration showing a metal ring before and after electroplating with silver.

Cheaper, less visually appealing, metals can be covered with more desirable materials such as silver or gold

This process makes jewellery cheaper by not requiring the entire item to be made from precious metal.

Example 2 - Making metals resistant to corrosion

Illustration showing a corroded pan on the left and an electroplated pan on the right.

Adding a layer of metal allows the original metal to be covered, reducing exposure to air and water

This adds a layer of sacrificial protection and prevents corrosion

Process of electroplating


Cutlery is electroplated to improve its appearance and to prevent corrosion. In this example we will look at electroplating a spoon with silver. 

Illustration of a beaker containing silver nitrate solution used in the electroplating process.

Step 1: Add the electrolyte


The electrolyte should be a solution of the plating metal such as silver nitrate solution.

Half equations


You need to know the half equations for the reactions at the anode and cathode.

Half equation at cathode:


Ag+ e- ➔ Ag

Half equation at anode:


Ag ➔ Ag+ e-

What happens to the metal at the anode?

it gains electrons to form positive ions

it loses electrons to form negative ions

it gains electrons to form negative ions 

it loses electrons to form positive ions

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What is the purpose of electroplating cutlery?

to improve its appearance

to reduce its weight

to prevent corrosion

to increase its strength

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Which electrode is the object being electroplated connected to?

negative anode

negative cathode

positive cathode

positive anode

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What is electroplating?

the process of removing metal from an object using electricity

the process of heating metal to a high temperature to change its properties

the process of shaping metal into different forms using molds

the process of coating an object with a thin layer of metal using electricity

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Which of the following is NOT an application of electroplating?

removing rust from metal surfaces

decorative coatings on jewellery and silverware

protective coatings on car parts to prevent corrosion

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What charge do metal ions have?

negative

positive 

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