Q10 of 30 Page 56

The silver jewellery becomes dull after prolonged use. Explain

Silver jewellery when exposed to air for a long time causes silver to react with the sulphur present in the air. A coating of silver sulphide is formed over the jewellery thus making it appear dull and black.

Black coating on silver jewellery:


2Ag + H2S (present in air) → Ag2S + H2


The black coating is of Ag2S. The chemical name is silver sulphide.


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