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Question
If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of
Options
CuSO4
CuCO3
Cu(NO3)2
CuO
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Solution
CuCO3
Explanation -
Copper metal kept open in the air, slowly undergoes the process of corrosion to form a characteristic blue-green coating on top of the metal surface. The corrosion of copper metal in air occurs in several steps :
`4"Cu"("s") + "O"_2("g") -> 2"Cu"_2"O"("s"),` red colour
`"Cu"_2"O"("s") + "O"_2("s") -> 2"CuO"("s"),` black colour
`2"CuO"("s") + "CO"_2("g") + "H"_2"O"("l") -> "CuCO"_3("s") + "CuCO"_3("s") + "Cu"("OH")_2("s"),` green colour
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