Answer: phosgene.
- A chlorobenzene
- B mustard gas
- C chloropicrin
- D phosgene
Correct answer: D. phosgene
Explanation: Chloroform is oxidised by air in light to poisonous carbonyl chloride (phosgene, COCl<sub>2</sub>); filling to the brim excludes air.
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.