For 2Cr + 2H3PO4 giving 2CrPO4 + 3H2, which is limiting when 0.50 mol Cr meets 0.75 mol H3PO4?

1. The coefficients are 2 and 2, so the required ratio is 1 mol Cr per 1 mol H3PO4. 2. The mixture supplies 0.50 mol Cr and 0.75 mol H3PO4. 3. Reacting all 0.50 mol of chromium would use only 0.50 mol of the acid. 4. That leaves 0.75 minus 0.50, which is 0.25 mol of acid unreacted. 5. Chromium therefore runs out first and is the limiting reactant. 6. Both coefficients are 2, so the coefficient cannot be the deciding reason. 7. Molar mass plays no part here, since the amounts are already given in moles. _Source: OpenStax Chemistry (CC BY 4.0), Ch 4 "Stoichiometry of Chemical Reactions", section 4.4 Reaction Yields_