Multiple choice general knowledge science & technology

Brass gets discoloured in air because of the presence of which of the following gases in air?

  1. Oxygen

  2. Hydrogen sulphide

  3. Carbon dioxide

  4. Nitrogen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Brass (an alloy of copper and zinc) discolours in air due to reaction with hydrogen sulphide, forming a dark layer of copper sulphide on the surface. Oxygen, carbon dioxide, and nitrogen do not cause this discolouration. This is a common chemistry phenomenon observed in brass objects.

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