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SSC MTS 2024 PYQ — Question 53

SSC MTS - 14/10/2024 - (4:00 PM - 5:30 PM) • General Awareness • Q53

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The black coating formed on silver jewellery is:

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Correct answer: D

Explanation

The correct answer is  option 4  i.e.   Ag₂S.

The black coating formed on silver jewellery is Ag₂S, which is silver sulfide. This occurs due to a chemical reaction between silver (Ag) and sulfur compounds present in the air, especially hydrogen sulfide (H₂S). When silver reacts with H₂S, it forms silver sulfide, a black compound that tarnishes the surface of the jewellery. This process is called tarnishing and is common when silver is exposed to air over time. The other compounds listed—AgCl (silver chloride), Ag₂CO₃ (silver carbonate), and AgNO₃ (silver nitrate)—do not cause the black coating typically seen on silver. 

Incorrect Options:

  • AgCl (Silver Chloride) – White in color, not black; forms in the presence of chlorine.

  • Ag₂CO₃ (Silver Carbonate) – Yellowish, not responsible for the black tarnish.

  • AgNO₃ (Silver Nitrate) – A chemical compound, not a product of tarnishing, and doesn’t form naturally on silver items.