Question

What happens when 2-bromobutane react with alcoholic KOH

Answer 1

Formation of but-2-bromobutane as the major product can be explained by Saytzeff's rule which states that if an alkyl halide undergoes elimination in two different ways, then the more highly substituted alkene i.e. having lesser number of hydrogen atoms on the doubly bonded carbon atoms, is the major product of a dehydrohalogenation reaction.

Answer 2

the answer is in the picture above . Hope it helps.