Question

Sita was very fond of wearing silver jewellery. She had kept her jewellery in a box. One day she observed tarnishing of the jewellery which was not worn for a long time. Why did it happen so ?



It's extremely urgent!!!!!!

Answer 1

Answer:

Explanation: it is because when it comes in contact with hydrogen sulphide

H2S to form a black coating called silver sulphide AG2S

Answer 2

Answer:

This is due to a process called tarnish.

Explanation:

The tarnishing is a corrosive process which usually takes place in ornamental metals. During tarnishing process, the metal becomes dull and grey. This is a limiting process, unlike formation of rust which corrodes and damages the metal while tarnishing simply affect the first layer of metal and that layer starts to protect the metal.

Silver, a transition metal, an inactive metal, undergoes tarnishing when it reacts with hydrogen sulfide and oxygen after long time. When hydrogen sulfide reacts with sulfide, it forms silver sulfide which is grey in color.

$2 A g+H_{2} S \rightarrow A g_{2} S+H_{2}$