Nucleophilic attack on the carbonyl carbonकार्बोनिल कार्बन पर नाभिकस्नेही आक्रमणNucleophilic attack on the carbonyl carbon
NCERT Fig 8.2 · Class 12 Chemistry · Chapter 8 · interactive diagram
Parts and what they mean
- Nucleophile Nu⁻ (electron-pair donor) (नाभिकस्नेही Nu⁻ (इलेक्ट्रॉन-युग्म दाता)) — Approaches the carbonyl carbon roughly perpendicular to the plane of its sp² orbitals.
- Planar carbonyl compound (sp² carbon) (समतलीय कार्बोनिल यौगिक (sp² कार्बन)) — δ+ carbon is the target of the nucleophile.
- Curved arrow 1: lone pair of Nu⁻ → carbonyl carbon (वक्र तीर 1: Nu⁻ का एकाकी युग्म → कार्बोनिल कार्बन) — A new C–Nu σ bond forms.
- Curved arrow 2: π electrons of C=O → oxygen (वक्र तीर 2: C=O के π इलेक्ट्रॉन → ऑक्सीजन) — Oxygen takes the electron pair and becomes negatively charged.
- Tetrahedral alkoxide intermediate (sp³) (चतुष्फलकीय ऐल्कॉक्साइड मध्यवर्ती (sp³)) — Hybridisation of carbon changes from sp² to sp³.
- Electrically neutral addition product (विद्युत-उदासीन योगज उत्पाद) — The alkoxide captures a proton from the reaction medium.
Steps
- Nu⁻ attacks the δ+ carbon; the π electrons move to oxygen.
- A tetrahedral alkoxide intermediate forms (sp² → sp³).
- It takes H⁺ from the medium: Nu and H have added across C=O.
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 8.2. Report a mistake