Inversion, racemisation and retentionप्रतिलोमन, रेसिमीकरण और धारणInversion, racemisation and retention
Class 12 Chemistry · Chapter 6 · interactive diagram
Parts and what they mean
- SN2: inversion of configuration (SN2: विन्यास का प्रतिलोमन) — The nucleophile attaches on the side opposite to the halogen, so the product has the inverted configuration.
- (−)-2-Bromooctane ((−)-2-ब्रोमोऑक्टेन) — NCERT example: treated with sodium hydroxide.
- (+)-Octan-2-ol ((+)-ऑक्टेन-2-ऑल) — –OH occupies the position opposite to the one Br had.
- SN1: racemisation (SN1: रेसिमीकरण) — A 50 : 50 mixture of the two enantiomers forms — optically inactive (±)-butan-2-ol.
- Optically active 2-bromobutane (प्रकाशिक सक्रिय 2-ब्रोमोब्यूटेन) — Its hydrolysis (SN1) gives (±)-butan-2-ol (NCERT).
- Planar (sp²) carbocation — achiral (समतलीय (sp²) कार्बोधनायन — अकिरैल) — OH⁻ can attack from either face with equal chance.
- Attack from the same side as Br (retention) (Br की ओर से आक्रमण (धारण)) — OH takes the position the bromide had: same configuration.
- Attack from the opposite side (inversion) (विपरीत ओर से आक्रमण (प्रतिलोमन)) — OH opposite to where Br was: inverted configuration.
- Retention of configuration (विन्यास का धारण) — No bond to the stereocentre is broken, so its arrangement of groups is kept. The sign of rotation may still change — a different compound can rotate light differently.
- (−)-2-Methylbutan-1-ol ((−)-2-मेथिलब्यूटेन-1-ऑल) — The –OH is on CH₂, not on the stereocentre.
- (+)-1-Chloro-2-methylbutane ((+)-1-क्लोरो-2-मेथिलब्यूटेन) — Configuration retained; rotation now (+).
Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake