In a vapor pressure table, what does the dotted line typically represent?

In a vapor pressure table, the dotted line typically represents the boiling point of the liquids at standard pressure. This is important because the boiling point is the temperature at which the vapor pressure of a liquid equals the atmospheric pressure. At this point, the liquid transitions to a gas.

The dotted line helps to visually indicate the temperature at which this equilibrium is achieved for various liquids under standard atmospheric conditions, providing a clear reference for understanding how different substances behave as they are heated.

This information is critical in practical applications, such as distillation or understanding how pressure affects boiling points and phase changes. Understanding where the boiling point lies in relation to the documented vapor pressures can also assist in predicting the behavior of substances under varying temperature and pressure conditions.