When an iron nail is dipped in copper sulphate solution, a brown coating of copper is formed on the surface of iron and the colour of copper sulphate solution changes from blue to light green.

 

This reaction shows that iron is more reactive than copper as it displaces copper from its solution and iron passes into solution as Fe2+ ions and ferrous sulphate solution is formed.

 

This reaction is a single displacement reaction.

 

The iron on the surface of the nail will swap places with some of the copper in the solution. So the iron nail will get a copper coating and the blue copper sulphate solution will start to change to green ferrous sulphate solution.

 

the iron (2+) wil go into the solution and Cu(2+) wil get deposited on the iron nail. so it wil turn reddish-brown and the colour of the solution wil also change from blue togreen.