Question

In an $S_{N}1$ reaction on chiral centres, there is:

• A. 100% retention
• B. 100% inversion
• C. 100% racemization
• D. inversion more than retention leading to partial recemization

Answer 1

The correct option is D inversion more than retention leading to partial recemization

$S_{N}1$ reaction gives racemic mixture with slight predominance of that isomer which corresponds to inversion because in reality, a completely free carbocation is not formed. The leaving group, in most cases, remains weakly attracted to the carbocation due to electrostatic forces, so it occupies the front side of the carbocation, and as a result, backside attack becomes more advantageous and less sterically hindered than front side attack and this results in slightly more inverted product.