Question

what is the black coloured coating on silver articles when it is exposed to atmosphere​

Answer 1

$\huge \fcolorbox{orange}{black}{Answer :-}$

Silver articles, when exposed to air become black after sometime. This is because the silver metal reacts with sulphur present in the atmosphere and forms silver sulphide. Thus, a layer of silver sulphide is formed on the surface of silver articles, because of which they appear dull and black.

Answer 2

Answer:

Silver sulphide

Explanation;

When silver is exposed to sulfur-containing gases in the air, it discolours and then darkens as it reacts with the gas to form a surface layer of tarnish. This process is called tarnishing.

H2S in air combines with air to form Silver sulphide.

Hope it helps you!!!