Question

why does the colour of copper sulphate solution change when an iron nail is dipped in it and chemical equation for the reaction invented it​

Answer 1

when an iron nail is dipped in copper sulphate the blue colour of copper sulphate changes to green due to the formation of iron sulphate as iron displace copper from its solution

this reaction will be written as

CuSo4 + Fe = FeSo4 + Cu

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)