JEE Main202427 Jan 2024Morning ShiftChemistryHaloalkanes and HaloarenesActual
The correct statement regarding nucleophilic substitution reaction in a chiral alkyl halide is ;
Options
- ARetention occurs in S N l reaction and inversion occurs in S N 2 reaction.
- BRacemisation occurs in S N l reaction and retention occurs in S N 2 reaction.
- CRacemisation occurs in both S N 1 and S N 2 reactions.
- DRacemisation occurs in S N 1 reaction and inversion occurs in S N 2 reaction.
Correct answer
D. Racemisation occurs in S N 1 reaction and inversion occurs in S N 2 reaction.
Step-by-step solution
In the 1 st step of S N 1 mechanism a carbocation is formed which is planar .Therefore the nucleophile can attack the carbocation from both the sides. When a nucleophile attacks the carbocation from the side where initially halogen was there,the product with retention in configuration is produce and when nucleophile attacks the carbocation from backside, the product with inversion in configuration is produce. Hence 50 % of the product will be with retention in configuration and rest 50 % will be with inversion in c