In the reaction 2 H_2 + O_2 → 2 H_2O, what is the number of moles of hydrogen gas (H_2) required to produce 0.253 mol of water (H_2O)?

• A. 0.379 mol
• B. 0.127 mol
• C. 0.506 mol
• D. 0.253 mol

Answer: (C)

Verified step by step guidance

1. Identify the balanced chemical equation: \$2\ H_2 + O_2 \rightarrow 2\ H_2O$.
2. Note the mole ratio between hydrogen gas (\(H_2\)) and water (\(H_2O\)) from the balanced equation. For every 2 moles of \(H_2\), 2 moles of \(H_2O\) are produced, so the ratio is \(\frac{2\ mol\ H_2}{2\ mol\ H_2O} = 1\).
3. Set up a proportion to find the moles of \(H_2\) needed to produce 0.253 moles of \(H_2O\): \(\text{moles of } H_2 = 0.253\ mol\ H_2O \times \frac{2\ mol\ H_2}{2\ mol\ H_2O}\).
4. Simplify the ratio and calculate the moles of \(H_2\) required based on the given moles of \(H_2O\).
5. Conclude that the moles of \(H_2\) required to produce 0.253 moles of \(H_2O\) is equal to the calculated value from the proportion.