JEE Main 2021 · 24 Feb · Shift 1 · Chemistry Q41

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ChemistrySingle correct+4 / -1Question 41 of 90

What is the major product formed by HI on reaction with $\mathrm{(CH_3)_3C{-}CH{=}CH_2}$ ?

Reactant: 3,3-dimethylbut-1-ene, (CH3)3C-CH=CH2.

1-Iodo-3,3-dimethylbutane

2-Iodo-2,3-dimethylbutane

2-Iodo-3,3-dimethylbutane

3-Iodo-2-methylpentane

Answer and worked solution

Official answer: B

Rearrangement. H⁺ adds to give the secondary cation $\mathrm{(CH_3)_3C{-}\overset{+}{C}H{-}CH_3}$ ; a methyl shift gives the tertiary $\mathrm{(CH_3)_2\overset{+}{C}{-}CH(CH_3)_2}$ , which takes I⁻: 2-iodo-2,3-dimethylbutane.

(B)

Topics:Alkenes Reactive intermediates

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JEE Main 2021 · 24 Feb · Shift 1, Chemistry question 41