Answer: SN2 substitution.
- A SN1 substitution
- B SN2 substitution
- C Elimination
- D Electrophilic substitution
Correct answer: B. SN2 substitution
Explanation: CN⁻ is a good nucleophile; it attacks the primary haloalkane from the back in a concerted single step, which is an SN2 mechanism.
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.