Identify the correct order of reactivity for the following compounds towards the S _ N 1 reaction: (I) (II) (III)

Step-by-step solution

The reactivity of alkyl halides towards the S _ N 1 reaction depends on the stability of the intermediate carbocation formed. The given compounds form the following carbocations upon the loss of a chloride ion: (I) Cyclopropyl cation (II) Cyclobutyl cation (III) Cyclopentyl cation The positively charged carbon atom in a carbocation is sp^2 hybridized, which has an ideal bond angle of 120^ . The stability of these cyclic carbocations is determined by the angle strain, which is the difference between the ideal bond a