 Boiling is a phase change where the liquid converts into the vapor. Here we have an example of T-butyl alcohol. As we heat the T-butanol, the kinetic energy of the molecules and the liquid increases. As we get closer and closer to the boiling point, the kinetic energy of the molecules and the liquid eventually become great enough so that they escape from the liquid. The liquid then turns into a vapor. Eventually, as we heat the substance, the temperature continues to increase until we reach the boiling point for the T-butanol, at which point the temperature will remain constant as long as there's any liquid T-butanol present.