Question

what happens when an iron nail is kept in a blue coloured copper sulphate?

Answer 1

It changes into iron sulphate cuso4+fe=feso4+cu

Answer 2

What happens when nails kept into a copper sulphate solution?

When an iron nail is kept in copper sulphate solution, a reddish brown coating is seen on the iron nail after sometime.

Also, the colour of the copper sulphate solution changes from blue to green.