Silver ware turns black after a period of time due to formation of:

Silverware turns black over time due to a process called tarnishing, which is a form of corrosion. When silver is exposed to air, it reacts with trace amounts of sulfur-containing gases, such as hydrogen sulfide (H2S), to form a thin, dark layer of silver sulfide (Ag2S) [4]. While silver is resistant to oxygen and does not form an oxide layer under normal conditions [3], it has a high affinity for sulfur. This chemical reaction (2Ag + H2S → Ag2S + H2) results in the characteristic black coating [3]. Although silver oxide and silver chloride can also be dark or grey, the primary cause of atmospheric tarnishing in everyday silverware is the formation of silver sulfide [3]. This coating can be removed by chemical reduction or abrasive polishing to restore the metal's original luster.

Sources

1. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 9: Distribution of World Natural Resources > silver > p. 34
2. [4] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > Activity 1.8 > p. 9
3. [3] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Activity 3.9 > p. 42
4. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.5 CORROSION > p. 53