Question:

Find the structure of A in following reaction

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Acid-catalysed hydration follows Markovnikov: OH goes to the carbon that holds the methyl group.
Updated On: Oct 1, 2026
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The Correct Option is B

Solution and Explanation

Step 1: Read the reaction:
The starting compound is 1-methylcyclohexene (a cyclohexene ring with a CH3 on one of the double-bond carbons). The reagent is conc. H2SO4 with H2O, which carries out acid-catalysed hydration of an alkene.

Step 2: Protonation (Markovnikov rule):
H+ adds to the double-bond carbon that already has more hydrogens. This puts the positive charge on the carbon that carries the methyl group, giving a tertiary carbocation, the most stable one.

Step 3: Attack by water:
A water molecule attacks the tertiary carbocation and forms an oxonium ion. The oxonium ion then loses H+ to give the alcohol, and the acid is regenerated.

Step 4: Product:
The OH group and the CH3 group end up on the same ring carbon, so A is 1-methylcyclohexanol. This is the structure in option (B).

Step 5: Why the other options are wrong:
Option (A) has OH on the carbon next to the CH3-carbon (2-methylcyclohexanol), which would need a less stable secondary carbocation. Options (C) and (D) contain a CH2OH group, which needs a carbon skeleton change or oxidation of the methyl group; plain hydration does neither.

Final Answer:
Hydration of 1-methylcyclohexene gives 1-methylcyclohexanol, option (B). \[ \boxed{\text{1-Methylcyclohexanol (option B)}} \]
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