What temperature show in a thermometer during distillation?

During distillation, the temperature shown on the thermometer corresponds to the boiling point of the liquid being vaporized. As the mixture is heated, the thermometer will indicate a stable temperature once the liquid reaches its boiling point, allowing for the separation of components based on their differing boiling points. The temperature may fluctuate if there are impurities or multiple components present, but a consistent reading indicates that the distillation process is effectively isolating a specific substance.