2VO + 3Fe2O3 → 6FeO + V2O5 If we start with 2 g of VO and 5.75 g of Fe2O3, which is the limiting reagent?
[Molar mass of V=47.87 g] [Molar mass of Fe=55.85 g]
Fe2O3
If you check, the reaction is already balanced 2 moles of VO = 3 moles of Fe2O3
2 × (47.87 + 16) = 3 × (2 × 55.85 + 3 × 16)
2(63.87 g) = 3 × (159.7 g)
127.74 g of VO = 478.1 g of Fe2O3
∴ 2 g of VO = 2×478.1127.74 = 7.50 g of Fe2O3
But only 5.75 g of Fe2O3 is present.
This Fe2O3 will get used up in the reaction and is the limiting reagent.