Answer:
2Fe⁺³ + Sn₂ → 2Fe⁺² + 2Sn⁺²
Explanation:
A redox reaction occurs between a compound that loses electrons and others that gain an electron. The first is being oxidized, and the other is being reduced.
In this situation, in the compound Fe₂O₃, the iron, has an oxidation number equal to +3, so it's Fe⁺³, and it will gain 1 electron to become Fe⁺². Because it was first dissolved in HCl, we must use the ion at the equation. The other compound Sn₂ will be oxidized to Sn⁺², so it will need to lose 2 electrons.
So, it will be necessary 2 Fe⁺³ for this reaction happen:
2Fe⁺³ + Sn₂ → 2Fe⁺² + 2Sn⁺²
