Consider the following alkyl bromides: (A) 3-Bromocyclohexene (B) Bromocyclohexane (C) 1-Bromohexane The correct decreasing order of their reactivity towards dehydrohalogenation with alcoholic KOH is:

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The rate of dehydrohalogenation (E2 elimination) is directly proportional to the stability of the major alkene formed. (A) 3-Bromocyclohexene undergoes dehydrohalogenation to form cyclohexa-1,3-diene, which is highly stable due to conjugation. (B) Bromocyclohexane undergoes dehydrohalogenation to form cyclohexene, which is stabilized by hyperconjugation (it is a disubstituted alkene). (C) 1-Bromohexane undergoes dehydrohalogenation to form hex-1-ene, which is a monosubstituted terminal alkene and is the least stabl