JEE Main 2024 — Chemistry Physical Chemistry

2024integermedium

Two reactions are given below:

$2{\mathrm{Fe}}_{(s)}+\frac{3}{2}{O}_{2(g)}\rightarrow {\mathrm{Fe}}_{2}{O}_{3(s)},\Delta {H}^{o}=-822\mathrm{kJ}/\mathrm{mol}$

${C}_{(s)}+\frac{1}{2}{O}_{2(g)}\rightarrow {\mathrm{CO}}_{(g)},\Delta {H}^{o}=-110\mathrm{kJ}/\mathrm{mol}$

Then enthalpy change for following reaction

$3{C}_{(s)}+{\mathrm{Fe}}_{2}{O}_{3(s)}\rightarrow 2{\mathrm{Fe}}_{(s)}+3{\mathrm{CO}}_{(g)}$

Official previous-year question

Held on 30 Jan 2024 · Verified 6 Jul 2026.

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Solution

Enthalpy change is the standard enthalpy of formation, in any general chemical reaction, the reactants undergo chemical changes and combine to give products. It can be represented by the following equation:

$\mathrm{Reactant}\rightarrow \mathrm{Product}$

From the given equations,

$2{\mathrm{Fe}}_{(s)}+\frac{3}{2}{O}_{2(g)}\rightarrow {\mathrm{Fe}}_{2}{O}_{3(s)},\Delta {H}^{o}=-822\mathrm{kJ}/\mathrm{mol}$ .........(i)

${C}_{(s)}+\frac{1}{2}{O}_{2(g)}\rightarrow {\mathrm{CO}}_{(g)},\Delta H^{\circ}=-110\mathrm{kJ}/\mathrm{mol}$ ....(ii)

$3{C}_{(s)}+{\mathrm{Fe}}_{2}{O}_{3(s)}\rightarrow 2{\mathrm{Fe}}_{(s)}+3{\mathrm{CO}}_{(g)},{\Delta H}_{3}=?$

The value of ${\Delta H}_{3}$ can be calculated as,

${\Delta H}_{3}=3\times {\Delta H}_{2}-{\Delta H}_{1}$

$=3(-110)+822$

$=492\mathrm{kJ}/\mathrm{mole}$

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JEE Main 2024 — Chemistry Physical Chemistry

2024integermedium

Two reactions are given below:

$2{\mathrm{Fe}}_{(s)}+\frac{3}{2}{O}_{2(g)}\rightarrow {\mathrm{Fe}}_{2}{O}_{3(s)},\Delta {H}^{o}=-822\mathrm{kJ}/\mathrm{mol}$

${C}_{(s)}+\frac{1}{2}{O}_{2(g)}\rightarrow {\mathrm{CO}}_{(g)},\Delta {H}^{o}=-110\mathrm{kJ}/\mathrm{mol}$

Then enthalpy change for following reaction

$3{C}_{(s)}+{\mathrm{Fe}}_{2}{O}_{3(s)}\rightarrow 2{\mathrm{Fe}}_{(s)}+3{\mathrm{CO}}_{(g)}$

Official previous-year question

Held on 30 Jan 2024 · Verified 6 Jul 2026.

Did you get this right?

Solution

$\mathrm{Reactant}\rightarrow \mathrm{Product}$

From the given equations,

$2{\mathrm{Fe}}_{(s)}+\frac{3}{2}{O}_{2(g)}\rightarrow {\mathrm{Fe}}_{2}{O}_{3(s)},\Delta {H}^{o}=-822\mathrm{kJ}/\mathrm{mol}$ .........(i)

${C}_{(s)}+\frac{1}{2}{O}_{2(g)}\rightarrow {\mathrm{CO}}_{(g)},\Delta H^{\circ}=-110\mathrm{kJ}/\mathrm{mol}$ ....(ii)

$3{C}_{(s)}+{\mathrm{Fe}}_{2}{O}_{3(s)}\rightarrow 2{\mathrm{Fe}}_{(s)}+3{\mathrm{CO}}_{(g)},{\Delta H}_{3}=?$

The value of ${\Delta H}_{3}$ can be calculated as,

${\Delta H}_{3}=3\times {\Delta H}_{2}-{\Delta H}_{1}$

$=3(-110)+822$

$=492\mathrm{kJ}/\mathrm{mole}$

Your note

JEE Main Physical Chemistry in other years

Keep practicing Physical Chemistry

Work through every JEE Main Physical Chemistry PYQ, year by year.

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JEE Main 2024 — Chemistry Physical Chemistry

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Solution

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JEE Main Physical Chemistry in other years

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JEE Main 2024 — Chemistry Physical Chemistry

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry