Question

When a strip of aluminium metal is dipped in a solution of ferrous sulphate, the pale green colour of the solution fades away. State the conclusion you can draw from this observation. Write the chemical equation for the reaction that occurs in this case.

Answer 1

Conclusion from the observation:
When a strip of aluminium metal is dipped in a solution of ferrous sulphate, the pale green colour of the solution fades away. This indicates that a displacement reaction is taking place. In this reaction, aluminium (Al), being more reactive than iron (Fe), displaces iron from the ferrous sulphate solution.

Chemical Equation for the Reaction:
The chemical equation for the displacement reaction is as follows: \[ \text{Al (s)} + \text{FeSO}_4 \text{(aq)} \rightarrow \text{Fe (s)} + \text{Al}_2\text{(SO}_4)_3 \text{(aq)} \] In this reaction:
- Aluminium (Al) displaces iron (Fe) from ferrous sulphate (FeSO₄).
- The iron (Fe) is precipitated as a solid, and aluminium sulphate (Al₂(SO₄)₃) is formed in the solution.

Thus, the fading of the pale green colour indicates the reduction of Fe²⁺ ions to metallic iron and the oxidation of aluminium to Al³⁺ ions, forming aluminium sulphate.