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Saturday, 31 October

JEE Main 2024 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 5 April 2024, Shift 2, Chemistry Q83

Question 83 of 90 in this shift, Chemistry question 23 of 30, Section B.

Combustion of 1 mole of benzene is expressed at C6H6(l)+152 O2(g)→6 CO2(g)+3 H2O(l)\mathrm{C_6H_6(l) + \frac{15}{2}\,O_2(g) \rightarrow 6\,CO_2(g) + 3\,H_2O(l)}. The standard enthalpy of combustion of 2 mol of benzene is −-'xx' kJ. x=x= ________. Given : 1. standard Enthalpy of formation of 1 mol of C6H6(l)\mathrm{C_6H_6(l)}, for the reaction 6 C (graphite)+3 H2(g)→C6H6(l)\mathrm{6\,C\,(graphite) + 3\,H_2(g) \rightarrow C_6H_6(l)} is 48.5 kJ mol−148.5\ \mathrm{kJ\ mol^{-1}}. 2. Standard Enthalpy of formation of 1 mol of CO2(g)\mathrm{CO_2(g)}, for the reaction C (graphite)+O2(g)→CO2(g)\mathrm{C\,(graphite) + O_2(g) \rightarrow CO_2(g)} is −393.5 kJ mol−1-393.5\ \mathrm{kJ\ mol^{-1}}. 3. Standard and Enthalpy of formation of 1 mol of H2O(l)\mathrm{H_2O(l)}, for the reaction H2(g)+12 O2(g)→H2O (l)\mathrm{H_2(g) + \frac{1}{2}\,O_2(g) \rightarrow H_2O\,(l)} is −286 kJ mol−1-286\ \mathrm{kJ\ mol^{-1}}.

Official answer

6535

NTA final key.

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

Same idea in other shifts

Asked 7× in all
  1. 8 Apr 2026, Shift 2 · Q74Consider the reaction 2H2S(g)+3O2(g)→2H2O(l)+2SO2(g)2\mathrm{H_2S(g)} + 3\mathrm{O_2(g)} \rightarrow 2\mathrm{H_2O(l)} + 2\mathrm{SO_2(g)} The magnitude of enthalpy…EasyNumerical value
  2. 6 Apr 2023, Shift 2 · Q83Consider the following data Heat of combustion of H2(g)\mathrm{H_2(g)} = −241.8-241.8 kJ mol−1^{-1} Heat of combustion of C(s)\mathrm{C(s)} =…MediumNumerical value
  3. 29 Jul 2022, Shift 2 · Q63C(s)+O2(g)→CO2(g)+400 kJ\mathrm{C(s)} + \mathrm{O_2(g)} \rightarrow \mathrm{CO_2(g)} + 400\ \mathrm{kJ}…MediumSingle correct
  4. 24 Jun 2022, Shift 2 · Q64At 25°C and 1 atm pressure, the enthalpies of combustion are given below: Substance | H2_2 | C (graphite) | C2_2H6_6(g)…MediumSingle correct
  5. 25 Jun 2022, Shift 2 · Q62At 25°C and 1 atm pressure, the enthalpy of combustion of benzene (l) and acetylene (g) are -3268 kJ mol−1\mathrm{kJ\ mol^{-1}} and -1300…MediumSingle correct
  6. 22 Jul 2021, Shift 2 · Q54If the standard molar enthalpy change for combustion of graphite powder is −2.48×102-2.48 \times 10^2 kJ mol−1^{-1}, the amount of heat generated…EasyNumerical value

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 108 of the 174 JEE Main shifts held from 2017 to 2026.