Brass gets discoloured in air because of the presence of which of the following gases in air?
A. Oxygen
B. Hydrogen sulphide
C. Carbon dioxide
D. Nitrogen
Opps, silly me.I choose B...please check it.I am very grateful!
Yes, the correct answer is B...thanks for reading through.🤦♀️I really thought I got it wrong.
The correct answer is B. Hydrogen sulphide.
Explanation:
Brass is an alloy made primarily of copper and zinc. When brass is exposed to air, it can react with certain gases to form a film or layer on its surface. This film is what causes the discoloration of brass.
Out of the options given, hydrogen sulphide (H2S) is the gas that commonly causes brass to become discolored. Hydrogen sulphide is a compound that is often present in air, especially in industrial areas or areas with high pollution levels. It is produced by both natural and human activities, such as industrial processes, volcanic activity, and the decomposition of organic matter.
When brass reacts with hydrogen sulphide in the air, it forms a layer of copper sulphide on the surface. Copper sulphide is a black or brownish compound, which gives the brass a discolored appearance.
It's worth noting that oxygen (option A) in the air can also contribute to the oxidation of brass, but it is not the primary cause of the discoloration in this case. Oxygen can lead to the formation of a thin layer of copper oxide on the surface of brass, which can give it a slight green or brownish tint.
Carbon dioxide (option C) and nitrogen (option D) are generally not directly involved in the discoloration of brass in air.