Explain why `Fe^(3+)` ion is more stable than `Fe^(2+)` ion in aqueous solution.

Explanation

The electronic configuration of `Fe^(2+)` and `Fe^(3+)` are `3d^(6)` and `3d^(5)` repectively.
Here, the electronic configuration of `Fe^(3+)` is more stable (`3d-` orbitals are all half-filled).
Hence, `Fe^(3+)`.