Chemistry
A strip of copper is placed in four different colourless salt solutions. They are KNO3, AgNO3, Zn(NO3)2 and Ca(NO3)2. Which one of the solutions will finally turn blue?
Electrolysis
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Answer
AgNO3 solution will turn blue.
Reason — Copper is unable to displace potassium, calcium and zinc from their nitrate solution as they are higher than copper in the metal activity series.
But silver being lower than copper in metal activity series gets displaced by copper and blue coloured copper nitrate is formed.
2AgNO3 + Cu ⟶ Cu(NO3)2 + 2Ag
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