CH3−CH(Br)−CH2−CH2−CH3alc.KOH 1 - pentene (minor)CH2=CH−CH2−CH2−CH3+2 - pentene(major)CH3−CH=CH−CH2−CH3
During dehydrohalogenation most stable alkene is formed by Saytzeff rule. According to Saytzeff’s rule an alkene with more number of hyperconjugated
hydrogens is the major product