The facts related to boiling can be expressed in the form of the following laws. These laws are known as laws of boiling.
1. Every liquid has a natural boiling point. The temperature at which a liquid starts boiling at normal atmospheric pressure is its normal boiling point. During boiling, the temperature remains constant until all the liquid changes to vapor.
2. Boiling point increases with the increase in pressure on the liquid and decreases when the pressure is lowered.
3. Boiling point of liquid increases due to the presence of dissolved substances. But the temperature of the vapor above the liquid remains equal to the boiling point of the pure liquid.