Final answer:
The addition of HBr to 2,4-hexadiene forms two possible products: 3-bromo-2-hexene (kinetic product) and 1-bromo-2-hexene (thermodynamic product). The temperature of the reaction influences which product predominates.
Step-by-step explanation:
The question asks to draw the addition products formed when one equivalent of HBr reacts with 2,4-hexadiene. When HBr is added to a diene like 2,4-hexadiene, it will react preferably according to Markovnikov's rule, where the hydrogen atom attaches to the carbon with the greater number of hydrogen atoms, and the bromine attaches to the carbon with the fewer hydrogen atoms. However, due to the conjugated diene system in 2,4-hexadiene, two products can form after HBr addition, a 1,2-addition (kinetic product) and a 1,4-addition (thermodynamic product). The 1,2-addition product is 3-bromo-2-hexene, while the 1,4-addition product is 1-bromo-2-hexene. At low temperatures, the kinetic product (1,2-addition) is favoured, and at higher temperatures, the thermodynamic product (1,4-addition) predominates.