Optically active 2-bromobutane undergoes racemization on treatment with a solution of KBr. Give a mechanism for this racemization. (b) In contrast, optically active butan-2-ol does not racemize on treatment with a solution of KOH. Explain why a reaction like that in part (a) does not occur. (c) Optically active butan-2-ol racemizes in dilute acid. Propose a mechanism for this racemization.