Question

The ascending order of relative rate of solvolysis of the following compounds is: \includegraphics[]{60.PNG} \begin{itemize} \item (A) Cyclohexyl bromide \item (B) Benzyl bromide \item (C) Phenylmethyl bromide \item (D) Allyl bromide \end{itemize}

• A. \( (D) <(A) <(B) <(C) \)
• B. \( (C) <(B) <(A) <(D) \)
• C. \( (C) <(B) <(A) <(D) \)
• D. \( (C) <(D) <(B) <(A) \)

Hint:

The rate of solvolysis is faster for compounds that form more stable carbocations, with allyl and benzyl carbocations being more stable than cyclohexyl carbocations.

Answer 1

The Correct Option is C

The rate of solvolysis of alkyl halides depends on the stability of the carbocation intermediate formed during the reaction. The more stable the carbocation, the faster the solvolysis reaction. The relative stability of the carbocations is influenced by the type of carbon and the substituent groups attached to it. - (A) Cyclohexyl bromide forms a less stable carbocation, so its rate of solvolysis is slower.
- (B) Benzyl bromide forms a highly stabilized carbocation due to resonance with the benzene ring, leading to a faster solvolysis.
- (C) Phenylmethyl bromide also forms a stable carbocation but less stable than the benzyl carbocation.
- (D) Allyl bromide forms a very stable carbocation due to resonance, making it the most reactive in solvolysis. Thus, the correct ascending order is \( (C) <(B) <(A) <(D) \).