Question

Why does the colour of copper sulphate solution change when an iron nail is kept immersed in it. Write the chemical equation for it?

Answer 1

Remember the reactivity series of metal

s, which says that Iron is more reactive than copper, therefore it can displace copper from its salts (here,copper sulphate).

The displacement reaction taking place can e written as :

Fe + CuSO4(aq) == FeSO4 + Cu

Iron + Copper Sulphate(aq) == Iron sulphate + copper

Now, enough basics, directly to question…

A fter 30 minutes:

1) The initial blue colour of copper sulphate solution is changed to light green colour of iron sulphate.

2) The initial silver colour of iron nail is changed to reddish-brown colour due to coating of copper metal on the nail.