Question

why does copper sulphate solution change its colour when iron nail is dipped in it​

Answer 1

Iron is more reactive than copper. So, when an iron nail is dipped in a copper sulphate solution, iron displaces copper from its solution to form iron sulphate, which is green in color. Hence, the blue color of copper sulphate solution changes into green color because of this displacement reaction.


When an "iron nail" dips into the solution of "copper sulphate" than iron, the copper sulphate displaces copper because "iron" is "more reactive" than "copper". Hence the colour of the solution for copper sulphate changes.

Answer 2

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

The reaction involved here is:

Fe (s) + CuSO4 (aq) → FeSO4 (aq) + Cu (s)