If a pure compound is distilled, the head temperature will becompared to the pot temperature. If however, an impurity is present that strongly interacts with the liquid molecules, then thehas to be increased in order to increase the vapor pressure of the liquid, ultimately toatmospheric pressure, allowing the liquid to boil. Thus, at boiling point, the pot temperature will befrom that of the head temperature.

If a pure compound is distilled, the temperature of the head will be compared to the temperature of the pot. However, if there is an impurity present that strongly interacts with the molecules of the liquid, then the temperature must be increased to increase the vapor pressure of the liquid, eventually to atmospheric pressure, allowing the liquid to boil. Therefore, at the boiling point, the temperature of the pot will be higher than the temperature of the head.

Explanation:

when temperatures increase, pressures also do so, thus reaching boiling points where liquid states become gaseous.