The colour of copper sulphate solution change when iron nail is dipped in it because the iron displaces sulphate from its copper sulphate solution because iron is more reactive than the copper so as a result ferrous sulphate is formed along with copper the colour changes because the colour of copper sulphate is blue whereas the colour of ferrous sulphate is green. CuSO4+Fe-------›FeSO4+Cu

The Color Change in Copper Sulphate Solution when an Iron Nail is Dipped in it

Introduction:
When an iron nail is dipped into a copper sulphate solution, a chemical reaction takes place, resulting in a change in the color of the solution. This reaction occurs due to the displacement of copper ions by iron atoms, leading to the formation of iron sulphate and the deposition of copper metal.

Chemical Equation:
The chemical equation for this reaction can be represented as follows:

Fe (s) + CuSO4 (aq) → FeSO4 (aq) + Cu (s)

Explanation:
1. Oxidation-Reduction Reaction:
The reaction between iron (Fe) and copper sulphate (CuSO4) involves an oxidation-reduction reaction. Iron atoms lose electrons, leading to oxidation, while copper ions gain electrons, leading to reduction.

2. Displacement Reaction:
The reaction between iron and copper sulphate is a displacement reaction. Iron, being more reactive than copper, displaces copper ions from the copper sulphate solution. As a result, copper atoms are deposited on the iron nail, causing a visible change in the color of the solution.

3. Formation of Iron Sulphate:
As iron displaces copper, iron sulphate (FeSO4) is formed as a product of the reaction. Iron atoms combine with sulphate ions from copper sulphate to form iron sulphate.

4. Deposition of Copper Metal:
The displaced copper ions from copper sulphate solution, CuSO4, are reduced to copper metal, Cu. These copper atoms get deposited on the surface of the iron nail, causing the color change in the solution.

5. Color Change:
Initially, the copper sulphate solution is blue in color. However, as the iron nail is dipped into the solution, the blue color fades away gradually. Simultaneously, a reddish-brown coating of copper metal forms on the iron nail. This change in color is an indicator of the occurrence of the displacement reaction and the deposition of copper metal.

In conclusion, when an iron nail is dipped into a copper sulphate solution, a displacement reaction takes place. Iron atoms displace copper ions, resulting in the formation of iron sulphate and the deposition of copper metal. This reaction causes a color change in the solution, from blue to colorless, while the iron nail becomes coated with a reddish-brown layer of copper.