Answer: Tertiary is faster by approximately 10 6 times.
- A Primary is faster, since SN1 solvolysis favours less hindered substrates
- B Both rates are essentially equal under these solvolysis conditions
- C Tertiary is faster by approximately 10<sup>6</sup> times
- D Tertiary is only modestly faster, by roughly a factor of 2
Correct answer: C. Tertiary is faster by approximately 10<sup>6</sup> times
Explanation: SN1 rate depends on the stability of the carbocation intermediate. Tertiary carbocations are far more stable (hyperconjugation + inductive effect), making (CH₃)₃CCl about a million times faster than n-BuCl in SN1.
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.