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

Step-by-step solution

The reactivity of a compound towards the S _ N 1 reaction depends on the stability of the intermediate carbocation formed after the departure of the leaving group. Let us analyze the carbocations formed from the given compounds: For compound (I), the departure of Cl ⁻ yields a primary allylic carbocation: CH ₂= CH - CH ₂⁺ . This carbocation is stabilized by resonance. For compound (II), the departure of Cl ⁻ yields a secondary allylic carbocation: CH ₂= CH - CH ⁺- CH ₃ . This carbocation is also stabilized by reson