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JEE Main levelOne or more correct optionsDifficulty 2 of 3o3259

The secondary bromide shown is solvolysed in warm aqueous ethanol. Select all correct statements about the cations and products.

  1. AA 1,2-hydride shift gives a tertiary cation
  2. BThe main substitution product has the OH or OEt on the tertiary carbon
  3. C2-Methylbut-2-ene is the main alkene
  4. DA methyl shift is preferred to a hydride shift because it gives a more stable cation

Answer: A, B, C

The compound is 2-bromo-3-methylbutane. A 1,2-hydride shift converts the secondary cation into a tertiary one, so the main substitution product is the tertiary alcohol/ether. Loss of a beta proton from this tertiary cation gives the most substituted alkene, 2-methylbut-2-ene. A methyl shift would give another secondary cation and brings no stabilisation, so the statement that methyl shift is preferred is false. Correct: first three.
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