JEE Main · 2005 · 08 May 2005 · Offline · Hydrocarbons

Acid catalyzed hydration of alkenes except ethene leads to the formation of

(A)primary alcohol
(B)secondary or tertiary alcohol✓ Correct
(C)mixture of primary and secondary alcohols
(D)mixture of secondary and tertiary alcohols

Answer: (B)

Solution

Acid-catalysed hydration runs through a carbocation and follows Markovnikov's rule, so the proton adds to one carbon and the

- OH

lands on the more substituted carbon, the one better able to carry positive charge. For any alkene beyond ethene this more-substituted carbon is itself secondary or tertiary, so the hydroxyl settles there and the product is a secondary or a tertiary alcohol depending on the alkene. Ethene is the lone exception, its symmetry allowing only the primary alcohol ethanol.

JEE Main · 2005 · 08 May 2005 · Offline · Single correct option

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