Question

Silver metal does not combine easily with oxygen but silver jewellery transishes after some time. How?

Answer 1

Silver metal does not react with oxygen but reacts with hydrogen sulphide gas in the air and forms a thin black layer of silver sulphide $\left(A{g}_{2}S\right)$ on it. Therefore, silver jewellery or ornaments tarnish due to the formation of a silver sulphide coating on their surfaces.