Question #44300

Consider the $S_N1$ solvolysis of the following alkyl chlorides in 80% aqueous ethanol at 298 K: \begin{itemize} \item[(I)] 2-Chloro-2-methylpropane \item[(II)] 1-Chloroadamantane \item[(III)] 2-Chloro-3,3-dimethylbutane \end{itemize} Evaluate the following statements regarding their thermodynamic and kinetic profiles: \begin{itemize} \item[(P)] In the gas phase, the ionization energy of the 1-adamantyl radical is lower than that of the $t$-butyl radical, yet I solvolyzes significantly faster than II in solution. \item[(Q)] The higher activation energy for the solvolysis of II compared to I is primarily due to steric exclusion, which prevents optimal solvent-shell organization and results in a less exothermic solvation enthalpy for the 1-adamantyl cation. \item[(R)] The solvolysis of III predominantly yields 2,3-dimethylbutan-2-ol (and its corresponding ethyl ether) via a 1,2-methyl shift, as the initial ionization produces a less stable secondary carbocation. \item[(S)] The initial heterolytic cleavage of III is kinetically faster than that of I due to the thermodynamic driving force of the subsequent rapid rearrangement to a tertiary carbocation. \end{itemize} Which of the following combinations of statements is CORRECT?