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Saturday, 31 October

JEE Main · Chemistry · Thermodynamics (Chemistry)

Enthalpy of Phase Transitions

JEE Main asked Enthalpy of Phase Transitions 3 times in 3 of the 108 shifts Lumi analysed, in 2022 and 2025. It belongs to Enthalpy and Hess's Law, in Thermodynamics (Chemistry) (Chemistry). The longest wait between two years asking it was 3 years. In 2025 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
3
in 3 shifts
Years
2 of 8
First asked
2022
last in 2025
Pattern
Occasional
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2022 and 2025. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.150.30’170’200’210.03’220’230’240.25’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 0 in 24 shifts · 2022: 1 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 in 18 shifts · 2025: 2 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
  • 20252 of 8
  • 20240 of 18
  • 20230 of 12
  • 20221 of 24
  • 20210 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.

  • Statement i/ii on melting of ice
  • Total enthalpy change over heating and phase change

Difficulty

Easy 2Medium 1Hard 0

1 of the 3 questions had a numerical answer.

Every question

All 3 questions

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

  1. 7 Apr 2025, Shift 1 · Q53Total enthalpy change for freezing of 1 mol of water at 10∘10^\circC to ice at −10∘-10^\circC is __________ (Given: ΔfusH=x\Delta_{fus}H = x…MediumSingle correct
  2. 3 Apr 2025, Shift 2 · Q53Given below are two statements: Statement I : When a system containing ice in equilibrium with water (liquid) is heated, heat is absorbed…EasyTwo statements
  3. 29 Jun 2022, Shift 1 · Q8217.0 g of NH3\mathrm{NH_3} completely vapourises at −33.42∘C-33.42^\circ\mathrm{C} and 1 bar pressure and the enthalpy change in the process is…EasyNumerical value

Shifts: 29 Jun 2022, Shift 1, 3 Apr 2025, Shift 2, 7 Apr 2025, 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