Organic Chemistry MCAT Practice Exam 2026 – The All-in-One Guide to Master Your Test Preparation!

The hydrolysis of alkyl halides can proceed through either an SN1 or SN2 mechanism, depending on the structure of the substrate.

In the case of primary alkyl halides, the reaction typically occurs via an SN2 mechanism. This pathway involves a single concerted step where the nucleophile (water or hydroxide ion in hydrolysis) attacks the carbon atom bearing the leaving group (the halide), resulting in the displacement of the leaving group and formation of the alcohol.

For tertiary alkyl halides, the SN1 mechanism is favored because it allows for the formation of a stable carbocation intermediate when the leaving group departs. The nucleophile then attacks the carbocation, leading to the final substitution product.

Secondary alkyl halides may react through either mechanism, where steric factors and the presence of good nucleophiles can influence the pathway taken. Therefore, the type of alkyl halide present determines whether the reaction will follow an SN1 or SN2 pathway, making the answer dependent on substrate structure. This explains why the hydrolysis of alkyl halides can be accomplished through either mechanism.