The reactivities of methyl chloride, propyl chloride and chlorobenzene are in
the order
[KCET 1988]
Based on the study of hyperconjugation and inductive action, propyl carbocation will be more stable than methyl carbocation. More is the number of methyl groups, more will be the extent of hyperconjugation due to more number of hydrogen atoms and inductive effect, so propyl carbocation is more stable due to delocalization of electrons Therefore, methyl chloride will be more reactive than propyl chloride in terms of reactivity.