NCEA Level 3 Organic Chemistry Reaction Schemes Practice Test

What is the outcome when tert-butyl bromide reacts with water under heat?

SN2; tert-butanol SN1; tert-butanol E2; isobutene SN1; tert-bromide

Correct Answer:

SN1; tert-butanol

Explanation:

When a tertiary alkyl bromide is heated in water, the bond to the bromide can break to form a stable tertiary carbocation. This unimolecular ionization step is the rate-determining part of the process. Water then acts as the nucleophile, attacking the carbocation to form the oxonium intermediate, which is deprotonated by water to yield tert-butanol. The reasons this pathway wins are that a tertiary carbocation is highly stabilized, so SN1 is favored over SN2 (which would be hindered by the bulky tert-butyl group), and water is a weak base, so elimination via E2 is not competitive under these conditions. The major product is tert-butanol.

Access more questions from this quiz

Continue to NCEA Level 3 Organic Chemistry Reaction Schemes Practice Test for more practice questions and the full quiz experience.

Access More Questions