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Why do silver articles turn blackish after long exposure to air?
AFormation of a silver sulphide layer
BFormation of a silver carbonate layer
CFormation of a silver oxide layer
DFormation of a silver chloride layer
Answer & Solution
Correct answer: A. Formation of a silver sulphide layer
1. Air contains traces of hydrogen sulphide.
2. Silver reacts with this hydrogen sulphide over time.
3. A black layer of silver sulphide (Ag2S) forms on the surface, turning it blackish.
4. The greenish copper layer is a carbonate, not the cause for silver, so that option is wrong.
_Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 8 "Metallurgy", p.115_
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