When 1.0 g of P4O10 reacts with 2.0 g of PCl5 according to the equation P4O10 + 6 PCl5 → 4 POCl3 + 5 Cl2, which reactant is the limiting reagent?

• A. Both are limiting reagents
• B. P4O10
• C. Neither is limiting; both are in excess
• D. PCl5

Answer: (B)

Verified step by step guidance

1. Write down the balanced chemical equation: \(\mathrm{P_4O_{10} + 6\ PCl_5 \rightarrow 4\ POCl_3 + 5\ Cl_2}\).
2. Calculate the molar masses of the reactants: find the molar mass of \(\mathrm{P_4O_{10}}\) and \(\mathrm{PCl_5}\) by summing the atomic masses of their constituent atoms.
3. Convert the given masses of each reactant to moles using the formula: \(\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\).
4. Use the stoichiometric coefficients from the balanced equation to determine the mole ratio required for the reaction: 1 mole of \(\mathrm{P_4O_{10}}\) reacts with 6 moles of \(\mathrm{PCl_5}\).
5. Compare the actual mole ratio of the reactants to the stoichiometric ratio to identify the limiting reagent. The reactant that produces fewer moles of product (or is consumed first) is the limiting reagent.