Question

Put two or three iron nails in the blue solutions of copper sulphate and after 15 to 20 minutes the colour of the solution turns green​

Answer 1

The reason for this change in colour is as follows:

Explanation:

• The reactivity series of metals states that Iron is more reactive than Copper, that is why it can displace copper from its salts (in this case - copper sulphate).

• The displacement reaction taking place can be written as:

• Fe + CuSO4(aqueous) = FeSO4 + Cu

• [Iron + Copper Sulphate(aqueous) = Iron sulphate + copper]

• After 30 minutes,  the original blue colour of copper sulphate solution turns to light green colour of iron sulphate.

• The original silver colour of iron nail is changed to reddish-brown colour due to deposition of copper metal on the nail.