The Zaitsev rule predicts that pent-2-ene is the major product in the dehydrohalogenation of 2-bromopentane, as it has a greater number of alkyl groups attached to the doubly bonded carbon atoms compared to other potential products.

Russian chemist Alexander Zaitsev formulated the Zaitsev rule in 1875. The rule states that in dehydrohalogenation reactions, the preferred product is the alkene with the greater number of alkyl groups attached to the doubly bonded carbon atoms.

b-Elimination involves the removal of a hydrogen atom from the b-carbon and a halogen atom from the a-carbon in a haloalkane. This process forms an alkene as a product.

The hydrolysis of optically active 2-bromobutane leads to the formation of (±)-butan-2-ol, illustrating racemisation with a mixture of products having the same and opposite configurations.

In SN₁ reactions of optically active alkyl halides, racemisation occurs due to the planar (achiral) nature of the sp² hybridized carbocation intermediate. The nucleophile can attack from either side of the plane, resulting in a mixture of products with the ...