Question

A student notices that her silver jewellery turned dull and had a grey-black coating over it after wearing for a few months. What results in the change in colour of the silver metal?

Options

• The polish over the jewellery was removed after wearing for a few months.

• The jewellery comes in contact with air, moisture and acids and corrodes.

• Dust particles over the jewellery change its colour.

• Its colour changes due to rusting.

Answer 1

The jewellery comes in contact with air, moisture and acids and corrodes.

Explanation:

Silver turns black due to a chemical reaction called tarnishing. Silver reacts with sulphur compounds (like hydrogen sulphide) in the air and moisture to form a thin, grey-black layer of silver sulphide (Ag₂S) on its surface.