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JEE Main levelOne or more correct optionsDifficulty 2 of 3o4258

The alcohol shown is dehydrated with concentrated sulfuric acid. Select all correct statements.

  1. A1-Methylcyclohexene is the major alkene.
  2. BWithout rearrangement the secondary cation can give two constitutionally different alkenes.
  3. CBoth E and Z isomers of methylcyclohexene are obtained.
  4. DA 1,2-hydride shift can convert the secondary cation into a tertiary cation.

Answer: A, B, D

The alcohol is 2-methylcyclohexanol. Loss of a hydrogen from C-2 gives the Saytzeff alkene 1-methylcyclohexene, and loss from C-6 gives 3-methylcyclohexene (two alkenes). A hydride shift from C-2 to C-1 gives a tertiary cation. Alkenes in six-membered rings do not show E/Z isomerism in the sense used here, so the third statement is false.
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