In the diagram, we see a distillation process. This is a separation process that takes advantage of differences in the boiling point of a mixture of liquids, so the more volatile liquid will evaporate and be recovered as distillate.
1) The first error seen is that the liquid solution mixture is not heated. In order to separate the liquids, we must heat the mixture by adding heat, and this heat is represented in the diagram with a flame.
2) The second mistake is the position of the thermometer, the thermometer must not be in contact with the liquid, it must be at the height of the bulb so that it is in contact with the vapor.
3) The third error is the exit of the coolant water. The water exchanges heat with the steam, so the steam cools and condenses and the water absorbs the heat, and its temperature increases, so it does not come out cold.
In the following figure we can see the mistakes: