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Saturday, 31 October

JEE Main · Chemistry · Chemical Kinetics

First Order Half-Life

JEE Main asked First Order Half-Life 6 times in 6 of the 108 shifts Lumi analysed, in 2022, 2023 and 2024. It belongs to Integrated Rate Equations, in Chemical Kinetics (Chemistry). The longest wait between two years asking it was 1 year. In 2022 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
6
in 6 shifts
Years
3 of 8
First asked
2022
last in 2024
Pattern
Comes in cycles
across the analysed shifts

Questions on this idea a shift, by year

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

00.10.20’170’200’210.14’220.07’230.05’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 0 in 24 shifts · 2022: 4 in 24 shifts · 2023: 1 in 12 shifts · 2024: 1 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
  • 20241 of 18
  • 20231 of 12
  • 20224 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.

  • Age from fractional radioactive content
  • Relation between times for first order

Difficulty

Easy 3Medium 2Hard 1

6 of the 6 questions had a numerical answer.

Every question

All 6 questions

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

  1. 1 Feb 2024, Shift 1 · Q86The ratio of 14C12C\frac{^{14}\mathrm{C}}{^{12}\mathrm{C}} in a piece of wood is 18\frac{1}{8} part that of atmosphere. If half life of…EasyNumerical value
  2. 13 Apr 2023, Shift 1 · Q87t87.5t_{87.5} is the time required for the reaction to undergo 87.5% completion and t50t_{50} is the time required for the reaction to undergo…EasyNumerical value
  3. 28 Jun 2022, Shift 2 · Q85A radioactive element has a half life of 200 days. The percentage of original activity remaining after 83 days is __________ . (Nearest…MediumNumerical value
  4. 26 Jun 2022, Shift 1 · Q84A flask is filled with equal moles of A and B. The half lives of A and B are 100 s and 50 s respectively and are independent of the…HardNumerical value
  5. 27 Jul 2022, Shift 2 · Q85[A] →\rightarrow [B] Reactant Product If formation of compound [B] follows the first order of kinetics and after 70 minutes the…EasyNumerical value
  6. 25 Jul 2022, Shift 2 · Q85For the decomposition of azomethane, CH3N2CH3(g)→CH3CH3(g)+N2(g)\mathrm{CH_3N_2CH_3(g) \rightarrow CH_3CH_3(g) + N_2(g)}, a first order reaction, the variation in…MediumNumerical valueHas a figure

Shifts: 26 Jun 2022, Shift 1, 28 Jun 2022, Shift 2, 25 Jul 2022, Shift 2, 27 Jul 2022, Shift 2, 13 Apr 2023, Shift 1, 1 Feb 2024, Shift 1.

Same topic

Other ideas in Integrated Rate Equations

Integrated Rate Equations has 15 ideas JEE Main has asked; 9 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas