Silver (Ag) typically turns black due to a chemical reaction with substances containing sulfur in the environment. The most common cause is hydrogen sulfide ($H_2S$), a gas present in the air.
The reaction forms silver sulfide ($Ag_2S$), a black compound, on the surface of the silver.
The simplified reaction is:
$2Ag + H_2S \rightarrow Ag_2S (black) + H_2$
Therefore, sulfur is the substance responsible for silver turning black.
Common salt (NaCl) is not used as a raw material for preparation of which one of the following compounds?
Which one of the following is the chemical formula of Hypobromous acid?
Which one of the following is not used as a raw material in the manufacture of glass?
Which one of the following statements about dihydrogen (H 2) is not correct?
Reaction of quick lime (CaO) with water to produce slaked lime (Ca(OH) 2) is an example of