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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceOtherEasyApplication

JEE Main 1 February 2024, Shift 2, Chemistry Q75

Question 75 of 90 in this shift, Chemistry question 15 of 30, Section A.

In the given reactions identify A and B H2+A→Pd/C\mathrm{H_2 + A \xrightarrow{Pd/C}} [figure: alkene with CH3\mathrm{CH_3} (upper left) and C2H5\mathrm{C_2H_5} (upper right) on the two carbons of C=C, and H (lower left), H (lower right)] CH3−C≡C−CH3+H2→Na/Liquid NH3\mathrm{CH_3-C\equiv C-CH_3 + H_2 \xrightarrow{Na/Liquid\ NH_3}} "B"

The figure, in words

Product of the first reaction is drawn as an alkene: left carbon bears CH3 (up) and H (down); right carbon bears C2H5 (up) and H (down), i.e. cis-2-pentene.
  1. (1)A : n-Pentane B : Cis-2-butene
  2. (2)A : 2-Pentyne B : trans-2-buteneOfficial answer
  3. (3)A : n-Pentane B : trans-2-butene
  4. (4)A : 2-Pentyne B : Cis-2-butene

Official answer

Option 2

NTA final key.

Chapter
Hydrocarbons
Topic
Alkenes and Alkynes
Idea tested
Stereoselective Alkyne Reduction

Same idea in other shifts

Asked 4× in all
  1. 4 Apr 2026, Shift 2 · Q64Compound (X) is subjected to the sequence of reactions as shown above. Molar mass of the major product (Y) formed is ________…MediumDiagram basedHas a figure
  2. 6 Apr 2024, Shift 1 · Q88The major product of the following reaction is P. CH3C=C−CH3\mathrm{CH_3C = C - CH_3}…MediumNumerical valueHas a figure
  3. 4 Aug 2021, Shift 1 · Q43Select the most suitable reagent for the following reduction reactionEasySingle correctHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.