NEET 2021 Physics and Chemistry

Major product formed in dehydrohalogenation reaction of 2-bromopentane is pent-2-ene because according to Saytzeff's rule, in dehydrohalogenation reactions, the preferred product is that alkene which has greater number of alkyl group(s) attached to the doubly bonded carbon atoms.
CH3−CH2−CH2−

Br

| CH

−CH3

OH−

────▶

CH3−CH2−CH=CH−CH3

Pent−2−ene(81%)

+

CH3−CH2−CH2−CH=CH2

Pent−1−ene(19%)