What is the major product of the reaction below, and what is the mechanism by which it is produced?
(CH3CH2)3CBr + F– –> ; temperature: 500C; solvent: water

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Correct Answer: A. (CH3CH2)3CF; SN1
This is an example of a SN1 reaction where first step is Br (good leaving group) dissociates to produces a carbocation (stabilized by the polar protic solvent, water). The tertiary carbocation intermediate is very stable, especially in the highly polar protic solvent water. The carbocation then combines with the strong nucleophile, the the F- ion. (the original substituent (Br) must be a better leaving group than the nucleophile (F-) in order for the reaction to occur). C and D are wrong because this is not an elimination reaction. B is wrong because this is not an SN2 reaction, due to the highly hindered substrate, and the type of solvent used in the reaction (SN2 reactions favor polar aprotic solvents, not polar protic solvents).
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