Considering that the question is What do you observe as you start heating the mixture of acetone and water in a distillation flask
then acetone will vaporise, condense in the condenser and will get collected in the condenser outlet
the reason for this chemical process is as follows
1) Initially when heating starts, acetone separates from the water because it has lower boiling point than that of water.
2) When the temperature becomes at 56 degree Celsius thermometer reading becomes constant. acetone converts to gas an is condensed in condenser outlet. The temperature becomes constant for some time because of the latent heat of evaporation (the heat goes between the space in the particles).
3) The boiling point of acetone is 56-degree Celsius and of water is 100 degree celsius to water takes more time to evaporate
4) For the above reason of difference in boiling point they separate from each other.”
In short the quick answer for the question
What do you observe as you start heating the mixture of acetone and water?
Answer is : Acetone get condensed in condenser during distillation and Water is left behind in the distillation flask.