Question

What effect does pressure and impurities have on the freezing and bolings points of liquids?

Answer 1

The impurities tends to increases the boiling point of the liquid whereas it tends to decrease the freezing point of the compound.
The pure liquid considered which is as solvent when added with some impurities its act as solute or some impure substance which do not allow the liquid to achieve its boiling point rather higher temperature will be required for the liquid added with impurities to reach the actual boiling point. Similarly freeing point points lower on addition of impurities i.e more cooling is required for the compound to make freeze

With decrease in the pressure, the freezing point of water or liquids will increase due to decreases in molecular interaction between the molecules. Lastly most of the liquids show expansion on increasing the temperature and ultimately they vaporise. With increase in pressure on the surface the expansion do not occur easily which delay vaporisation. Thus, the boiling point is increases on increasing the pressure