NEET 2018 · ChemistryPrevious Year Question
Which of the following carbocations is expected to be the most stable? (Each is a cyclohexadienyl-type cation bearing an substituent on the ring, with the positive charge located at varying ring positions relative to the group.)
Answer: (A) (A). \textbf{Answer:} (a) \textbf{Solution:} is a strong electron-withdrawing group exerting a (inductive) effect that destabilises an adjacent positive charge.

- A.(A)✓
- B.(B)
- C.(C)
- D.(D)
Correct Answer
(A) (A)
Solution & Explanation
\textbf{Answer:} (a) \textbf{Solution:} is a strong electron-withdrawing group exerting a (inductive) effect that destabilises an adjacent positive charge. The effect falls off rapidly with distance, so the cation in which the positive carbon is located farthest from experiences the least destabilisation and is the most stable. Hence (a).
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