Final answer:
Silver tarnishes through a chemical reaction with hydrogen sulfide gas in the air, forming silver sulfide. This darkens the silver's appearance. Silver sulfide is the product of the tarnishing process, not silver oxide, carbonate, or nitride.
Step-by-step explanation:
When silver tarnishes, it undergoes a chemical reaction where it is oxidized to silver sulfide. This process occurs as silver reacts with hydrogen sulfide gas in the air. The reaction can be represented by the following chemical equation: 2 Ag(s) + H₂S(g) → Ag₂S(s) + H₂ (g). The tarnished silver appears dark because of the presence of silver sulfide, which has a starkly different appearance compared to the shiny, metallic surface of untarnished silver. Tarnish can be removed using special polishes, though this process also removes a thin layer of silver.
The correct answer to how silver tarnishes is that it is oxidized to silver sulfide. This means of the given options, (2) It is oxidized to silver sulfide, is the accurate answer. The sulfur contributing to tarnish primarily comes from traces of sulfur in the air or from certain foods.