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Saturday, 10 October

JEE Main Chemistry · Hydrocarbons

Alkanes and Free Radicals in JEE Main

Alkanes and Free Radicals (Chemistry, Hydrocarbons) came 12 times in 12 of the 42 JEE Main shifts Lumi analysed, across 9 distinct ideas. 11 of them came in 2024–26; it was last asked in 2026.

Questions
12
in 12 shifts
Ideas asked
9
3 asked more than once
Numerical answer
5
42% of its questions
Pattern
Comes in cycles
last asked 2026
Questions each year
0360’170’200’210’221’233’242’256’26

In the shifts Lumi analysed for each year.

Difficulty and format
Easy 2Medium 8Hard 2

Format

  • Numerical value5 Q
  • Single correct4 Q
  • Two statements2 Q
  • Diagram based1 Q
Ideas inside the topic
9 ideas
Where it sits

Part of Hydrocarbons, which had 34 questions in all. Alkanes and Free Radicals accounts for 35% of them. In Lumi's JEE taxonomy it belongs to Organic Chemistry.

Some questions sit in other chapters too: Aldehydes, Ketones and Carboxylic Acids, Haloalkanes and Haloarenes, Organic Chemistry: Some Basic Principles and Techniques.

Every question

All 12 Alkanes and Free Radicals questions

Newest first, each with its options and official answer.

  1. 2 Apr 2026, Shift 1 · Q73One mole of an alkane (x) requires 88 mole oxygen for complete combustion. Sum of number of carbon and hydrogen atoms in the alkane (x)…EasyNumerical value
  2. 2 Apr 2026, Shift 2 · Q64The compound (X) on heating in the presence of anhydrous AlCl3_3 and HCl gas gives 2,4-dimethyl pentane (ii) aromatization gives toluene…EasySingle correct
  3. 5 Apr 2026, Shift 2 · Q72RMgI when treated with ice cold water liberated a gas which occupied 1.4 dm3^3/g at STP. The gas produced is further reacted with iodine…MediumNumerical value
  4. 6 Apr 2026, Shift 1 · Q65Given below are two statements: Statement I: Methane can be prepared by decarboxylation of sodium ethanoate, Kolbe's electrolysis of…MediumTwo statements
  5. 6 Apr 2026, Shift 2 · Q72An alkane (Y) requires 8 moles of oxygen for complete combustion and on chlorination with Cl2/hν\mathrm{Cl_2}/h\nu, (Y) gives only one…MediumNumerical value
  6. 8 Apr 2026, Shift 2 · Q65n-Butane on monochlorination under photochemical condition gives an optically active compound "P". "P" on further chlorination gives…MediumSingle correct
  7. 2 Apr 2025, Shift 1 · Q64Consider the following compound (X) H−C≡C−CH2−CH(CH3)−CH3\mathrm{H-C{\equiv}C-CH_2-CH(CH_3)-CH_3} with the carbons numbered I (the terminal ≡\equivC-H…MediumSingle correctHas a figure
  8. 2 Apr 2025, Shift 2 · Q66Given below are two statements : Statement (I) : Neopentane forms only one monosubstituted derivative. Statement (II) : Melting point of…MediumTwo statements
  9. 9 Apr 2024, Shift 1 · Q74In the following sequence of reaction, the major products B and C respectively are : [figure: Cl-cyclobutane-Br (1,3-disubstituted…HardSingle correctHas a figure
  10. 29 Jan 2024, Shift 1 · Q76The final product A formed in the following multistep reaction sequence isMediumDiagram basedHas a figure
  11. 31 Jan 2024, Shift 1 · Q87Number of alkanes obtained on electrolysis of a mixture of CH3COONa\mathrm{CH_3COONa} and C2H5COONa\mathrm{C_2H_5COONa} is _________.MediumNumerical value
  12. 6 Apr 2023, Shift 1 · Q89Number of bromo derivatives obtained on treating ethane with excess of Br2\mathrm{Br_2} in diffused sunlight is ________HardNumerical value