Resonance-stabilised allyl and benzyl carbocationsअनुनाद से स्थायी ऐलिल और बेन्ज़िल कार्बोधनायनResonance-stabilised allyl and benzyl carbocations

Class 12 Chemistry · Chapter 6 · interactive diagram

Parts and what they mean

• Allyl carbocation CH₂=CH–CH₂⁺ (ऐलिल कार्बोधनायन CH₂=CH–CH₂⁺) — The C=C π electrons shift towards the positive carbon: two equivalent resonance structures, positive charge delocalised.
• Benzyl carbocation C₆H₅CH₂⁺ (बेन्ज़िल कार्बोधनायन C₆H₅CH₂⁺) — Four resonance structures — the reason benzylic halides show high SN1 reactivity.
• Structure I: + on the CH₂ carbon (संरचना I: CH₂ कार्बन पर +) — The ring π bond next to CH₂⁺ moves to form an exocyclic C=CH₂.
• Structure II: + on an ortho carbon (संरचना II: ऑर्थो कार्बन पर +) — Exocyclic C=CH₂; positive charge on the ortho carbon.
• Structure III: + on the para carbon (संरचना III: पैरा कार्बन पर +) — Shifting another ring π bond moves the charge to para.
• Structure IV: + on the other ortho carbon (संरचना IV: दूसरे ऑर्थो कार्बन पर +) — Charge now on the second ortho carbon.

Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake