Why does silver turn black when exposed to air?
T. Bhaskar Bangalore Answer 1:Metals have a tendency to change back to their original state of existence that is the ore from which these been extracted and they do so by their interaction with the environment. The atmospheric air contains moisture and certain dissolved gases like oxygen, carbon dioxide, sulphur dioxide, hydrogen sulphide and the like. Silver metal is extracted mainly from its sulphide ores like argentite (silver glance) as a white lustrous metal, which remains untarnished in air free from hydrogen sulphide. But in the presence of trace amounts of hydrogen sulphide in atmosphere, silver forms a film of silver sulphide that is black. Prof.S.K. Aggarwal Amritsar College of Engineering & Technology Amritsar Answer 2: Silver tarnish is the discoloration that occurs on silver. Silver is not appreciably affected by dry or moist air that is free from ozone, halogens, ammonia, and sulphur compounds. The presence of hydrogen sulphide in any material that silver comes into conta
