Question

$50.0\, kg$ of $N_{2(g)}$ and $10.0\, kg$ of $H_{2(g)}$ are mixed to produce $NH_{3(g)}$. Identify the limiting reagent in the production of $NH_3$ in this situation.

• A. Nitrogen
• B. Hydrogen
• C. Can not be predicted
• D. None of these

Answer 1

Answer: (B)

Hydrogen

Answer 2

The balanced chemical reaction is ${N2 +3H2<=> 2NH3}$ From the above balanced equation, 1 mol of $N_{2(g)}$ reacts with 3 moles of $H_{2(g)}$. $\therefore$ Moles of $N_{2}=\frac{50,000\,g}{28\,g\,mol^{-1}}=1785.71\,mol$ or, Moles of $H_{2}=\frac{10,000\,g}{2.106\,g\,mol^{-1}}=4960.3\,mol$ $\therefore 1785.7\, mol$ of $N_2$ react with $3 ? 1785.7\, mol = 5357.1\, mol$ but we have $4960.3 \,mol$ of $H_2$ only. Therefore, $H_2$ is a limiting reagent.