JEE Main 2022 · 25 Jun · Shift 1 · Chemistry Q73

← JEE Main 2022 · 25 Jun · Shift 1

ChemistrySingle correct+4 / -1Question 73 of 90

The product formed in the following reaction.
$\mathrm{(CH_3)_2C=CH_2+H\text{-}C(CH_3)_3\xrightarrow{H^\oplus}\ ?}$
is :

\mathrm{(CH_3)_2CH\text{-}CH_2\text{-}CH_2\text{-}CH(CH_3)_2}

\mathrm{(CH_3)_2CH\text{-}CH_2\text{-}C(CH_3)_3}

\mathrm{CH_3\text{-}CH(CH_3)\text{-}CH(CH_3)\text{-}CH(CH_3)_2}

\mathrm{(CH_3)_3C\text{-}C(CH_3)_3}

Answer and worked solution

Official answer: B

Acid-catalysed alkylation. $\mathrm{H^+}$ adds to isobutylene to give the tert-butyl cation; it adds to a second isobutylene, giving a $\mathrm{C_8}$ tertiary cation; hydride transfer from isobutane ends the chain.

Product. $\mathrm{(CH_3)_3C\text{-}CH_2\text{-}CH(CH_3)_2}$ , 2,2,4-trimethylpentane (iso-octane).

(B)

Topics:Alkanes Reactive intermediates

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JEE Main 2022 · 25 Jun · Shift 1, Chemistry question 73