Molar ratio of Fe to Al is 2:2.
Explanation:
Wherever we write the chemical equation it must be a balanced one and the states of all the reactants and products to be mentioned, so that the reaction can be clearly understood. To write the molar ratio of the one of the reactant and product, we have to use the balanced equation as, here 2 moles of Al is required to produce 2 moles of iron (Fe).
Fe₂O₃(s) + 2 Al(s) → 2 Fe(s) + Al₂O₃(s)
So the molar ratio of Fe to Al is 2:2.