JEE Main 2024 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 30 January 2024, Shift 2, Chemistry Q82

Question 82 of 90 in this shift, Chemistry question 22 of 30, Section B.

Two reactions are given below:

2\mathrm{Fe_{(s)}} + \frac{3}{2}\mathrm{O_{2(g)}} \to \mathrm{Fe_2O_{3(s)}},\ \Delta H^\circ = -822\ \mathrm{kJ/mol}

\mathrm{C_{(s)}} + \frac{1}{2}\mathrm{O_{2(g)}} \to \mathrm{CO_{(g)}},\ \Delta H^\circ = -110\ \mathrm{kJ/mol}

Then enthalpy change for following reaction

3\mathrm{C_{(s)}} + \mathrm{Fe_2O_{3(s)}} \to 2\mathrm{Fe_{(s)}} + 3\mathrm{CO_{(g)}}

is ________ kJ/mol.

Official answer

492

NTA final key.

Chapter: Thermodynamics (Chemistry)
Topic: Enthalpy and Hess's Law
Idea tested: Hess's Law

Same idea in other shifts

Asked 4× in all

2 Apr 2026, Shift 1 · Q54Consider the following data. (i) $\mathrm{2Al(s)+6HCl(aq)\rightarrow Al_2Cl_6(aq)+3H_2(g)}+1200$ kJ/mol (ii)…HardSingle correct
25 Jul 2022, Shift 1 · Q82The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are $-2220.0\ \mathrm{kJ\,mol^{-1}}$ ,…EasyNumerical value
2 Apr 2017 (offline) · Q31Given $\mathrm{C_{(graphite)}+O_2(g)\rightarrow CO_2(g)}$ ; $\Delta_rH^\circ=-393.5\ \mathrm{kJ\,mol^{-1}}$ …EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.