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

Answer 1

(c) sulphide
Silver reacts with hydrogen sulphide gas in the air and forms a think black layer of silver sulphide $\left(A{g}_{2}S\right)$ on it. Silver jewellery or ornaments become dull because of the formation of silver sulphide coating on their surfaces.