Consider the following reaction occurring in the blast furnace. Fe 3O 4(s) + 4CO(g) xrightarrow 3Fe(l) + 4CO 2(g) x kg of iron is produced when 2.32times10 3\, kg Fe 3O 4 and 2.8times10 2\, kg CO are brought together in the furnace. The value of x is \ \ \ \ \ \ (nearest integer). Given: Molar mass of Fe 3O 4 = 232\, g\,mol -1 Molar mass of CO = 28\, g\,mol -1 Molar mass of Fe = 56\, g\,mol -1

Chemistry · Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

JEE Main 2025 — 24 January, Morning Shift — Question 46

Consider the following reaction occurring in the blast furnace.

$\mathrm{Fe_3O_4(s) + 4CO(g) \xrightarrow{} 3Fe(l) + 4CO_2(g)}$

$x$ kg of iron is produced when $2.32\times10^3\,\mathrm{kg}$ $\mathrm{Fe_3O_4}$ and $2.8\times10^2\,\mathrm{kg}$ $\mathrm{CO}$ are brought together in the furnace.

The value of $x$ is $\_\_\_\_\_\_$ (nearest integer).

Given: Molar mass of $\mathrm{Fe_3O_4} = 232\,\mathrm{g\,mol^{-1}}$ Molar mass of $\mathrm{CO} = 28\,\mathrm{g\,mol^{-1}}$ Molar mass of $\mathrm{Fe} = 56\,\mathrm{g\,mol^{-1}}$

Answer: 420

Numerical answer — enter this value.

Step-by-step solution

Moles of $\mathrm{Fe_3O_4}$ $= \dfrac{2.32\times10^3 \times 10^3}{232} = 10000\,\mathrm{mol}$

Moles of $\mathrm{CO}$ $= \dfrac{2.8\times10^2 \times 10^3}{28} = 10000\,\mathrm{mol}$

Stoichiometry $= 1\,\mathrm{mol}\,\mathrm{Fe_3O_4}$ requires $4\,\mathrm{mol}\,\mathrm{CO}$

Required CO for $10000$ mol $\mathrm{Fe_3O_4}$ $= 4\times10000 = 40000\,\mathrm{mol}$

Available CO = $10000\,\mathrm{mol}$ $\Rightarrow \mathrm{CO}$ is limiting.

Moles of $\mathrm{Fe_3O_4}$ reacting $= \dfrac{10000}{4} = 2500\,\mathrm{mol}$

Moles of Fe produced $= 3\times2500 = 7500\,\mathrm{mol}$

Mass of Fe $= 7500 \times 56 = 420000\,\mathrm{g} = 420\,\mathrm{kg}$

Thus, the value of $x$ is $420$ .

Answer key and solution verified before publishing.

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Exam: JEE Main 2025
Paper: 24 January, Morning Shift
Subject: Chemistry
Chapter: Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry
Topic: Chemical Equations, Stoichiometry and Limiting Reagent