Can somebody explain what happened in this experiment? The mixture of toluene/water was heated to its boiling point (without a condenser) of about 84C. Over the course of under a few minutes, the boiling point increased rapidly and then remained constant at about 96C (more or less- it jumped up and down a lot but stayed in the same range). The constant final temperature is because the toluene was all vaporized and just water remained, correct? But since the mixture was an azeotrope mixture, shouldn't the concentration have remained constant (and the toluene not completely vaporized before the water)? Was this supposed to happen or was it probably due to measurement error when preparing the mixture?