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Saturday, 31 October

JEE Main · Chemistry · Thermodynamics (Chemistry)

Standard Enthalpy of Reaction

JEE Main asked Standard Enthalpy of Reaction 2 times in 2 of the 108 shifts Lumi analysed, in 2021 and 2023. It belongs to Enthalpy and Hess's Law, in Thermodynamics (Chemistry) (Chemistry). The longest wait between two years asking it was 2 years.

Updated 2026-10-24

Times asked
2
in 2 shifts
Years
2 of 8
First asked
2021
last in 2023
Pattern
Occasional
across the analysed shifts

Questions on this idea a shift, by year

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

00.050.10’170’200.03’210’220.07’230’240’250’26

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

Shift by shift

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

  • 20260 of 9
  • 20250 of 8
  • 20240 of 18
  • 20231 of 12
  • 20220 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.

  • Heat evolved per gram of mixture
  • Reaction enthalpy from formation enthalpies

Difficulty

Easy 1Medium 1Hard 0

2 of the 2 questions had a numerical answer.

Every question

All 2 questions

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

  1. 11 Apr 2023, Shift 1 · Q83Solid fuel used in rocket is a mixture of Fe2O3\mathrm{Fe_2O_3} and Al (in ratio 1:2). The heat evolved (kJ) per gram of the mixture is…MediumNumerical value
  2. 17 Mar 2021, Shift 1 · Q54The standard enthalpies of formation of Al2O3\mathrm{Al_2O_3} and CaO are −1675 kJ mol−1-1675\ \mathrm{kJ\ mol^{-1}} and −635 kJ mol−1-635\ \mathrm{kJ\ mol^{-1}}…EasyNumerical value

Shifts: 17 Mar 2021, Shift 1, 11 Apr 2023, Shift 1.

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