Fundamentals of Organic ChemistryChemistryHaloalkanes and Haloarenes
Which of the following statements are true for the S _ N 1 reaction of alkyl halides? (I) Both the alkyl halide and the nucleophile are involved in the transition state of the rate-determining step. (II) The reaction proceeds with inversion of configuration at the substitution centre. (III) The reaction proceeds via the formation of a carbocation intermediate. (IV) The order of reactivity of alkyl halides is 3^ > 2^
Options
- A(II), (IV) and (V)
- B(I), (II), (V) and (VI)
- C(III), (IV) and (VI)
- D(I), (II) and (VI)
Correct answer
C. (III), (IV) and (VI)
Step-by-step solution
Statement (I) is incorrect because the rate-determining step of an S _ N 1 reaction involves only the alkyl halide, not the nucleophile. Statement (II) is incorrect because S _ N 1 reactions proceed with racemization (both retention and inversion of configuration), whereas S _ N 2 reactions proceed with inversion. Statement (III) is correct as the S _ N 1 mechanism involves the heterolytic cleavage of the C - X bond to form a carbocation intermediate. Statement (IV) is correct because the reactivity in S _ N 1 depe