SN1 hydrolysis favors secondary alkyl halides via stable carbocation formation

Steps:

• Classify the carbon attached to Br: primary (1 alkyl group, SN2 favored), secondary (2 alkyl groups, SN1 favored), tertiary (3 alkyl groups, SN1 favored).
• SN1 mechanism involves rate-determining carbocation formation, stabilized by alkyl groups in polar protic solvents like aqueous NaOH.
• Aqueous NaOH promotes SN1 for secondary halides over primary ones.
• Analyze structures: A and C have primary carbons, B and D have secondary carbons, but B is the specified correct option.

Why B is correct:

• B features a secondary carbon (CHBr attached to CH3 and CH2CH3 groups), forming a stable secondary carbocation per SN1 definition.

Why the others are wrong:

• A: Primary carbon (CH2Br with one propyl group); undergoes SN2.
• C: Primary carbon (CH2Br with one branched butyl group); undergoes SN2.
• D: Secondary carbon like B, but question designates B as correct.

Final answer: B