Question

What changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails dipped in copper sulphate solution for about 30 minutes?

What happens when iron nails are put into copper sulphate solution?

Answer 1

When an iron nail is placed in copper sulphate solution, then iron sulphate solution and copper metal are formed.

\[\ce{\underset{(Blue solution)}{\underset{Copper sulphate}{CuSO4_{(aq)}}} + \underset{(Grey)}{\underset{Iron}{Fe_{(s)}}} -> \underset{(Greenish solution)}{\underset{Iron sulphate}{FeSO4_{(aq)}}} + \underset{(Red-brown)}{\underset{Copper}{Cu_{(s)}}}}\]

In this process, iron displaces copper from a copper sulphate solution. The deep blue hue of copper sulphate solution diminishes as it transforms into a light green solution of iron sulphate. A red-brown layer of copper metal is deposited on the surface of iron metal. This displacement reaction occurs because iron is more reactive than copper.