Iron Sulphate
Explanation
The reaction between iron and copper sulphate is a classic example of a single displacement reaction based on the reactivity series of metals. In such reactions, a more reactive metal displaces a less reactive metal from its salt solution.
Detailed Analysis:
- Reactivity Principle: Iron ($Fe$) is more reactive than Copper ($Cu$) according to the electrochemical series. Consequently, iron has the ability to displace copper from an aqueous solution of copper sulphate.
- Chemical Reaction: When iron is added to a copper sulphate solution, the following chemical change occurs:
$Fe(s) + CuSO_4(aq) \rightarrow FeSO_4(aq) + Cu(s)$ - Colour Change:
- The original solution of Copper Sulphate ($CuSO_4$) is blue.
- As the reaction proceeds, Ferrous Sulphate (Iron(II) Sulphate) is formed. The solution turns light green due to the formation of $FeSO_4$.
- A reddish-brown deposit of copper metal forms on the surface of the iron.
Key Takeaway:
The green colour observed during the reaction of iron with copper sulphate solution is caused by the formation of Iron(II) Sulphate ($FeSO_4$), as iron displaces copper from the solution.