JEE Main · 2019 · Shift-ImediumMOLE-193

For the reaction N2(g) + 3H2(g) - 2NH3(g), identify dihydrogen (H2) as a limiting reagent in the following reaction…

Some Basic Concepts (Mole Concept) · Class 11 · JEE Main Previous Year Question

Question

For the reaction \ceN2(g)+3H2(g)>2NH3(g)\ce{N2(g) + 3H2(g) -> 2NH3(g)}, identify dihydrogen (\ceH2\ce{H2}) as a limiting reagent in the following reaction mixtures:

Options
  1. a

    28 g of \ceN2\ce{N2} + 6 g of \ceH2\ce{H2}

  2. b

    35 g of \ceN2\ce{N2} + 8 g of \ceH2\ce{H2}

  3. c

    56 g of \ceN2\ce{N2} + 10 g of \ceH2\ce{H2}

  4. d

    14 g of \ceN2\ce{N2} + 4 g of \ceH2\ce{H2}

Correct Answerb

35 g of \ceN2\ce{N2} + 8 g of \ceH2\ce{H2}

Detailed Solution

🧠 The Dihydrogen Bottleneck Haber's process (%N2+3H22NH3\%{N2 + 3H2 \rightarrow 2NH3}) is a numbers game. You need three times as much Hydrogen (H2H_2) as Nitrogen (N2N_2). If you have less than that, the Hydrogen is your Limiting Reagent. Test every mixture by comparing the Nitrogen "potential" to the available Hydrogen.

🗺️ Strategic Roadmap Step 1: Convert masses to moles.

  • (a) 1mol1\,mol N2N_2 + 3mol3\,mol H2H_2: Perfect balance (1:31:3).
  • (b) 35g35\,g N2N_2 (1.25mol1.25\,mol) + 8g8\,g H2H_2 (4mol4\,mol): Need 3.75mol3.75\,mol H2H_2. We have 44. (Nitrogen limits).
  • (c) 56g56\,g N2N_2 (2mol2\,mol) + 10g10\,g H2H_2 (5mol5\,mol): Need 6mol6\,mol H2H_2. We only have 55. Hydrogen is Limiting.

Answer: (c) 56 g of N2 + 10 g of H2\boxed{\text{Answer: (c) 56 g of N2 + 10 g of H2}}

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For the reaction N2(g) + 3H2(g) - 2NH3(g), identify dihydrogen (H2) as a limiting reagent in the… (JEE Main 2019) | Canvas Classes