Which gas causes brass to discolor in air?

by

(A) Oxygen
(B) Hydrogen Sulphide
(C) Nitrogen
(D) None of these

🧠 Explanation:

  • Brass is an alloy of copper and zinc, and when exposed to air, it can undergo chemical reactions.
  • Hydrogen sulphide in the atmosphere reacts with the copper content in brass to form a dark tarnish.
  • This tarnishing is a form of corrosion that leads to discoloration of the metal surface over time.
  • The gas responsible for this reaction is hydrogen sulphide.