Question

Which one of the carbocations from the following is most stable?

• A.
• B.
• C.
• D.

Hint:

Carbocations are stabilized by resonance and electron-donating groups, while electron-withdrawing groups tend to destabilize them. Look for conjugated systems or groups that can delocalize the positive charge to predict carbocation stability.

Answer 1

The Correct Option is B

Carbocation stability is determined by stabilizing factors. These include:

• Electron-donating groups providing inductive support.
• Resonance stabilization through delocalization of the positive charge.
• Degree of alkyl substitution: tertiary > secondary > primary carbocation stability.

Analysis of each option:

1. This primary carbocation lacks resonance or electron-donating stabilization and is thus less stable.
2. This tertiary carbocation, the correct choice, is the most stable due to three alkyl groups donating electron density via the inductive effect, which stabilizes the positive charge.
3. This secondary carbocation lacks resonance stabilization, making it less stable than a tertiary carbocation.
4. This primary carbocation lacks resonance stabilization.

Consequently, the second option, a tertiary carbocation, is the most stable among the provided choices.