Give reason why:
Colour of the solution changes when iron nail is dipped in copper sulphate solution.
Iron nails when left dipped in blue copper sulphate solution become brownish in colour and the blue colour of copper sulphate fades away.
Fe + CuSO4→ FeSO4 + Cu
The above reaction is a type of displacement reaction in which one element displaces another element from its compound and takes its place therein. In the reaction, Fe replaces Cu and form a new compound.