Final answer:
The correct product of the reaction between 1,3-butadiene and HBr is 3-bromo-1-butene, which is not listed in the given options. The provided answers do not correctly account for the major product formed in the electrophilic addition of HBr to 1,3-butadiene.
Step-by-step explanation:
1,3-butadiene is a type of diene and has two double bonds that can react with electrophiles. When reacting with HBr, an electrophilic addition reaction occurs. According to Markovnikov's rule, the hydrogen atom is added to the carbon with the greatest number of hydrogen atoms, and the bromine atom is added to the carbon with the least number of hydrogen atoms.
In the case of 1,3-butadiene, the HBr molecule adds across the conjugated diene system. The hydrogen atom adds to one of the terminal carbon atoms of the diene, and the bromine adds to the other terminal carbon atom. However, due to stability considerations involving the formation of more stable secondary carbocation intermediates, the bromine tends to add to the more substituted carbon, leading to the formation of 3-bromo-1-butene as the major product, rather than 1-bromobut-2-ene (1) or 2-bromobut-1-ene (2).
Therefore, the correct product of the reaction between 1,3-butadiene and HBr is 3-bromo-1-butene, which is not given in the provided options. None of the options (1-bromobut-2-ene, 2-bromobut-1-ene, 1,2-dibromobutane, and 1,4-dibromobutane) correctly represents the major product of this reaction.