Chemistry - GOC Question with Solution | TestHub

All four cations are secondary, so degree of substitution alone cannot choose the answer. In $\mathrm{II}$, the neighboring ${\mathrm{CH}}_2$ and ${\mathrm{CH}}_3$ groups provide five adjacent $\mathrm{C}-\mathrm{H}$ bonds for hyperconjugation. $\mathrm{I}$ and $\mathrm{III}$ provide four, and IV provides two. The source's hyperconjugation model therefore favors $\mathrm{II}$.