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Question
The articles made of silver metal become dark on prolonged exposure to air. This is due to the formation of a layer of its:
(a) oxide
(b) hydride
(c) sulphide
(d) carbonate
Solution
(c) sulphide
Silver reacts with hydrogen sulphide gas in the air and forms a think black layer of silver sulphide (Ag2S) on it. Silver jewellery or ornaments become dull because of the formation of silver sulphide coating on their surfaces.
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