How does the composition of the distillate change over the course of a distillation?

During distillation, the composition of the distillate changes as the distillation progresses due to differences in the volatility of the components in the mixture. Initially, the distillate is rich in the more volatile component because it vaporizes at a lower temperature compared to the less volatile component. As distillation continues, the more volatile component is gradually removed from the mixture, and the remaining liquid becomes enriched with the less volatile component. Consequently, by the end of the distillation process, the distillate can become relatively rich in the less volatile component, as that is what remains in the flask. This reflects the principle that the separation during distillation is primarily driven by the volatility of the components, leading to a dynamic change in composition throughout the operation.