If 2 g of hydrogen reacts with 16 g of oxygen, what is the limiting reagent?

1. Balanced equation: 2 H2 + O2 -> 2 H2O. 2. Moles of H2 = 2 / 2 = 1 mole. 3. Moles of O2 = 16 / 32 = 0.5 mole. 4. By ratio, 1 mole H2 needs 0.5 mole O2; both are exact. 5. Wait: H2:O2 = 2:1 means 1 mole H2 reacts with 0.5 mole O2. 6. Here we have exactly 1 mole H2 and 0.5 mole O2; both are fully used. 7. So neither is left over both are used up exactly. But the question expects oxygen as the binding reagent in case of skew so answer follows the calculation: both used up exactly. _Source: Selina Concise Chemistry ICSE Class 10, Ch 5 'Mole Concept and Stoichiometry'_