Answer :
The balanced equation is given as,
2Al³⁺ + 3H₂O + Br⁻ → 2 Al + BrO³⁻ + 6H⁺
Explanation:
H₂O + Br⁻ + Al³⁺ → Al + BrO₃⁻ + H⁺
Here the half reactions are:
Al³⁺→ Al [reduction]
Br⁻ → BrO₃⁻ [oxidation]
Now we have to balance the half reactions as,
Al³⁺ + 3e⁻ → Al
To balance H atoms we have to add water and electrons.
3H₂O + Br⁻→ BrO³⁻ + 6H⁺ + 6e⁻
Now we have to balance the electrons as,
2Al³⁺ + 6e⁻ → 2 Al
3H₂O + Br⁻→ BrO³⁻ + 6H⁺ + 6e⁻
Now we have to add both the equations as,
2Al³⁺ + 6e⁻ + 3H₂O + Br⁻ → 2 Al + BrO³⁻ + 6H⁺ + 6e⁻
6 electrons on both sides of the equation gets cancelled and so the balanced reaction can be written as,
2Al³⁺ + 3H₂O + Br⁻ → 2 Al + BrO³⁻ + 6H⁺