Allyl chloride undergoes hydrolysis at a rate faster than n-propyl chloride - why?

Explanation

Hydrolysis ( solvolysis) is in general an `S_(N)1` reaction. Allyl chloride undergoes easy hydrolysis because the resulting allyl cation (obtain on C-Cl bond cleavage) is stabilised considerably by resonance. On the other hand, n-propyl chloride, which is expected to produce a very unstable `1^(@)` carbocation, does not undergo hydergo hydrolysis by the `S_(N)1` mechanism. It undergoes hydrolysis by the relatively slow `S_(N)2` process.