Question

Which one of the following will most readily be dehydrated in acidic solution?

• A. Secondary alcohol with carbonyl nearby

  

• B. Secondary alcohol

  

• C. Tertiary alcohol

  

• D. Diol

  

Hint:

Carbocation stability increases with resonance → adjacent carbonyl group enhances dehydration rate.

Answer 1

The Correct Option is A

To determine which compound will most readily undergo dehydration in an acidic solution, let's analyze each option:

1. Secondary alcohol with carbonyl nearby:

The presence of a carbonyl group nearby can significantly stabilize the carbocation intermediate formed during dehydration due to resonance and inductive effects. This stability increases the likelihood of dehydration.

2. Secondary alcohol:

Secondary alcohols can undergo dehydration, but without the influence of nearby functional groups like carbonyl, they are less favorable than the first option.

3. Tertiary alcohol:

Tertiary alcohols undergo dehydration readily because the resulting tertiary carbocation is quite stable. However, in the context of this question where specific stability factors are considered, the carbonyl-adjacent secondary alcohol is more readily dehydrated due to additional stabilization by resonance.

4. Diol:

Diols can undergo dehydration, but the reaction mechanism may involve pinacol rearrangement, which is less straightforward compared to simple dehydration.

Considering the above points, the secondary alcohol with a carbonyl nearby is most readily dehydrated in acidic solution due to the additional resonance stabilization provided by the carbonyl group, enhancing the stability of the intermediate.