Question

Which one of the following metals is protected from corrosion by a layer of its own oxide?

Options

• Aluminium

• Copper

• Silver

• Gold

Answer 1

Aluminium

Explanation:

When exposed to air, aluminium (Al) produces a thin, protective layer of aluminium oxide (Al₂O₃). By serving as a barrier and preventing oxygen and moisture from penetrating to the underlying metal, this oxide layer stops additional corrosion. While aluminium, other metals, including copper (Cu), silver (Ag), and gold (Au), do not produce protective oxide layers.