Corrosion/tarnish of alloys: Brass gets discoloured in air due to the presence of which gas? Identify the gas that reacts with copper in brass to form a dark sulfide film. Choose the correct gas.
General Knowledge
General Science
Difficulty: Easy
Choose an option
Answer
Correct Answer: Hydrogen sulfide (H2S)
Explanation
What is being asked?The atmospheric gas responsible for the dark tarnish on brass.
Given data
- Alloy: Brass (Cu + Zn)
Concept/ApproachH2S in air reacts with copper to form copper sulfide films, causing discoloration; oxygen alone forms oxide patina more slowly, while CO2 and N2 are largely inert here.
Final AnswerHydrogen sulfide (H2S)