Question

Why does the colour of copper sulphate solution change when an iron nail is dipped in it?

Answer 1

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When an iron nail dipped in the copper sulphate solution, iron displaces copper from the copper sulphate because iron is more reactive than copper. Therefore, the colour of copper sulphate solution changes.

Answer 2

Answer:

Iron lies above in the reactivity series and thus more reactive than copper. As a result, the more reactive metal (iron) displaces a less reactive metal (copper) from its salt solution (copper sulphate solution). Hence, the change in color.