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Saturday, 31 October

JEE Main · Chemistry · Thermodynamics (Chemistry)

Formation and Combustion

JEE Main asked Formation and Combustion 7 times in 7 of the 108 shifts Lumi analysed, in 2021, 2022, 2023, 2024 and 2026. It belongs to Enthalpy and Hess's Law, in Thermodynamics (Chemistry) (Chemistry). The longest wait between two years asking it was 2 years. In 2022 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
7
in 7 shifts
Years
5 of 8
First asked
2021
last in 2026
Pattern
Asked most years
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2021, 2022, 2023, 2024 and 2026. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.10.20’170’200.03’210.10’220.07’230.05’240’250.11’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 1 in 24 shifts · 2022: 3 in 24 shifts · 2023: 1 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 1 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20261 of 9
  • 20250 of 8
  • 20241 of 18
  • 20231 of 12
  • 20223 of 24
  • 20211 of 24
  • 20200 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Numerical value is the usual form. Skill tested: calculation.

  • Enthalpy of reaction from formation enthalpies
  • Enthalpy of combustion from formation enthalpies

Difficulty

Easy 2Medium 5Hard 0

4 of the 7 questions had a numerical answer.

Every question

All 7 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  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. 5 Apr 2024, Shift 2 · Q83Combustion 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…MediumNumerical value
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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

Shifts: 22 Jul 2021, Shift 2, 24 Jun 2022, Shift 2, 25 Jun 2022, Shift 2, 29 Jul 2022, Shift 2, 6 Apr 2023, Shift 2, 5 Apr 2024, Shift 2, 8 Apr 2026, Shift 2.

Same topic

Other ideas in Enthalpy and Hess's Law

Enthalpy and Hess's Law has 23 ideas JEE Main has asked; 12 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas