Answer: From the opposite side to the leaving group.
- A From the same side as the leaving group
- B From the opposite side to the leaving group
- C From the top only
- D From a random direction
Correct answer: B. From the opposite side to the leaving group
Explanation: SN2 is a backside attack: the nucleophile approaches 180° opposite to the leaving group, causing inversion of configuration (Walden inversion).
SN2 proceeds in a single step with backside attack and inversion of configuration, while SN1 forms a planar carbocation intermediate first, leading to racemisation.
Concept context
Study carbon-halogen compounds: how they are made, how they react via SN1/SN2 and elimination, their stereochemistry, and their environmental impact.