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

Explanation

The reaction between copper(II) sulphate and iron is represented as `underset("Blue")(CuSO_(4(aq)))+Fe_((s))tounderset("Light green")(FeSO_(4(aq)))+underset("Brown")(Cu_((s)))`
Light green Brown In this displacement reaction, a more active element iron displaces another less reactive element from its compound copper(II) sulphate. The brown copper metal gets deposited on the iron nails. The colour of the solution changes from blue to light green due to the formation of ferrous sulphate (having `Fe^(2+)` ions).