MHT CET202620 April 2026Evening ShiftChemistryHaloalkanes and HaloarenesActual
What is the major product formed when 2-bromopentane reacts with alcoholic KOH?
Options
- APent-1-ene
- BPent-2-ene
- CPentane
- DPentan-2-ol
Correct answer
B. Pent-2-ene
Step-by-step solution
Reaction of 2-bromopentane with alcoholic KOH undergoes dehydrohalogenation (E2 elimination). CH₃-CH(Br)-CH₂-CH₂-CH₃ alc. KOH, CH₃-CH=CH-CH₂-CH₃ + CH₂=CH-CH₂-CH₂-CH₃ According to Zaitsev's rule, the more substituted alkene is formed as the major product. Pent-2-ene is a disubstituted alkene, whereas pent-1-ene is a monosubstituted alkene. Thus, pent-2-ene is the major product. Answer: Pent-2-ene