Answer: Optically active.
- A Aromatic under most conditions encountered
- B Optically active
- C Racemic as frequently observed in practice
- D Achiral in many documented cases
Correct answer: B. Optically active
Explanation: Optically active compounds contain at least one chiral centre and rotate plane-polarised light either to the left (levorotatory) or to the right (dextrorotatory).
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.