MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

Dehydrohalogenation of 2-bromobutane ( CH _3 -CH _2 -CH(Br)-CH _3) involves the removal of a hydrogen atom from a -carbon and the bromine atom from the -carbon. There are two -carbons in 2-bromobutane, leading to two possible alkene products: 1. Removal of hydrogen from C1 yields 1-butene ( CH _3 -CH _2 -CH=CH _2). 2. Removal of hydrogen from C3 yields 2-butene ( CH _3 -CH=CH-CH _3). According to Zaitsev's rule, the major product in a dehydrohalogenation reaction is the more substituted alkene, as it is thermodynamically more stable. 2-butene is a disubstituted alkene, whereas 1-butene is a monosubstituted alkene. Thus, 2-butene ( H _3 C-CH=CH-CH _3) is the major product. Answer: H _3 C-CH=CH-CH _3