Answer:
Step-by-step explanation:
Aside the boiling point of water, another colligative property that can be used to identify pure water (or not) is the freezing point. Water freezes at 0 °C, but with the presence of impurities, there is a freezing point depression of the water. Thus, if the water is not pure, the liquid could freeze at a temperature lower than 0 °C (with a negative sign like -8 °C).