Consider the following reactions A $\xrightarrow[\text{(ii) } H_3O^+]{\text{(i) } CH_3MgBr}$ B $\xrightarrow[573\text{ K}]{Cu}$ 2-methyl-2-butene The mass percentage of carbon in A is ______.

JEE Main 2020 · ChemistryNumerical answerNumerical valueMediumMulti-step

JEE Main 9 January 2020, Shift 2, Chemistry Q50

Question 50 of 75 in this shift, Chemistry question 25 of 25, Section B.

Consider the following reactions A

\xrightarrow[\text{(ii) } H_3O^+]{\text{(i) } CH_3MgBr}

\xrightarrow[573\text{ K}]{Cu}

2-methyl-2-butene The mass percentage of carbon in A is ______.

Official answer

66.65 to 66.70

NTA final key (Jan 2020). Any value in the range scored.

Chapter: Alcohols, Phenols and Ethers
Topic: Alcohols and Phenols
Idea tested: Grignard Synthesis of Alcohols

Same idea in other shifts

Asked 3× in all

11 Apr 2023, Shift 1 · Q90[figure: 4-hydroxybutanal, $\mathrm{OHC{-}CH_2CH_2CH_2{-}OH}$ (y mole)] $\xrightarrow[\mathrm{H_3O^+}]{x\ \text{mol of MeMgBr}}$ [figure:…MediumNumerical valueHas a figure
26 Jul 2022, Shift 1 · Q75Which reactant will give the following alcohol on reaction with one mole of phenyl magnesium bromide (PhMgBr) followed by acidic…MediumOtherHas 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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.