Given below are two statements : Statement (I) : Benzyl chloride reacts faster in S_N1 mechanism than ethyl chloride. Statement (II) : Ethyl carbocation intermediate is less stabilized by hyperconjugation than benzyl carbocation by resonance. In the light of the above statements, choose the correct answer from the options given below :
A. Both Statement I and Statement II are true
The rate of S_N1 reaction depends on the stability of the carbocation intermediate formed during the rate-determining step. Benzyl chloride undergoes ionization to form a benzyl carbocation (C_6H_5CH_2^+), whereas ethyl chloride forms an ethyl carbocation (CH_3CH_2^+). The benzyl carbocation is highly stabilized by the delocalization of the positive charge over the benzene ring through resonance. On the other hand, the ethyl carbocation is stabilized only by hyperconjugation involving three -hydrogens. Since resonance provides significantly greater stabilization than hyperconjugation, the benzyl carbocation is much more stable than the ethyl carbocation. Consequently, benzyl chloride reacts faster in the S_N1 mechanism than ethyl chloride. Thus, Statement I is true. Statement II correctly explains that the ethyl carbocation intermediate is less stabilized by hyperconjugation compared to the resonance stabilization of the benzyl carbocation. Thus, Statement II is also true. Both Statement I and Statement II are true. Answer: Both Statement I and Statement II are true
Related: Chemistry — Haloalkanes and Haloarenes · All PYQ Banks