Question

Find the order of formation of alcohol from alkene from the following.

• A. \(3^{\circ} > 1^{\circ} > 2^{\circ}\)
• B. \(3^{\circ} > 2^{\circ} > 1^{\circ}\)
• C. \(1^{\circ} > 2^{\circ} > 3^{\circ}\)
• D. \(1^{\circ} > 3^{\circ} > 2^{\circ}\)

Hint:

Acid-catalysed hydration goes through carbocations, so 3 > 2 > 1.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
In acid-catalysed hydration, the alkene takes a proton to form a carbocation, and water then adds to it. The easier the carbocation forms, the faster that alcohol forms.

Step 2: Apply:
Carbocation stability is \(3^\circ > 2^\circ > 1^\circ\), because alkyl groups stabilise the positive charge through the \(+I\) effect and hyperconjugation.
By Markovnikov's rule, the proton adds so that the more stable carbocation forms. So tertiary alcohols form most readily and primary alcohols least readily.

Step 3: Order:
\[ 3^\circ > 2^\circ > 1^\circ \]
This is option B. The other options place primary alcohols too high, which would need the least stable carbocation to form fastest.

Final Answer:
The order of formation is \(3^\circ > 2^\circ > 1^\circ\), option (B). \[ \boxed{3^\circ > 2^\circ > 1^\circ} \]