[Cesium-137]

Hi all,
So I ran into a question today when refluxing with a dean stark trap. If solvents boil off independently of one another, starting with the lower boiling solvent, how can a dean stark trap work? I'm refluxing benzene and Conc. HBr. Benzene should boil at about 80 C, water at 100, and the HBr/water azeotrope at 128ish. If this is the case, shouldn't the benzene just reflux away, never getting hotter than its boiling point and thus not allowing the water created in the reaction to boil/get trapped? Am I looking at this in the wrong way? Also, how can I be sure that I'm not trapping HBr in the dean stark? Thanks!!

[MissPhosgene]

Benzene forms an azeotrope with water at 69.3 celsius. I'm pretty sure the composition is 91.1% benzene.

Benzene returns because it is less dense than water. 0.8765 g/mL