Answer: 0° (optically inactive).
- A +180°, indicating a single pure dextrorotatory enantiomer is present
- B -180°, indicating a single pure levorotatory enantiomer is present
- C 0° (optically inactive)
- D A variable value that changes randomly each time it is measured
Correct answer: C. 0° (optically inactive)
Explanation: A racemic mixture contains equal amounts of (+) and (-) enantiomers; their rotations exactly cancel, giving zero net optical rotation.
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.