Test for purity[edit | edit source]
A liquid will boil sharply at a constant temperature (e.g. water would boil at 100C). This is called the boiling point. An impure liquid will boil at a higher temperature if a solid impurity is dissolved in it. If it contains a liquid impurity with a lower boiling point, it will boil for a greater range of temperature. If a solid is pure, it melts sharply at its melting point. An impure solid will melt below this point.