Which reaction mechanism characterizes the alkaline hydrolysis of 2-bromo-2-methylpropane (tert-butyl bromide) with aqueous sodium hydroxide?
Answer and explanation
Correct answer: B. SN1 mechanism involving a rate-determining tertiary carbocation step
- Step 1: Tertiary alkyl halides are sterically hindered, preventing backside nucleophilic attack. Step 2. The C-Br bond ionizes in the rate-determining step to form a stable tertiary carbocation intermediate. Step 3. Hydroxide then rapidly attacks the planar carbocation to form tert-butanol via an SN1 pathway. Answer: SN1 mechanism involving a rate-determining tertiary carbocation step. Why not the others: SN2 occurs for primary halides; E2 dominates with strong sterically hindered bases.
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