(2) The temperature at which thepressure of the gas (air pressure) isequal to the vapour pressure of theliquid is known as the boiling pointof that liquid. The boiling point of theliquid is directly influenced by thepressure over the liquid. If theexternal pressure is less than 1atmosphere, then the boiling point ofthe liquid would be less than itsnormal boiling point. Similarly, if thepressure is more than 1 atmosphere,the boiling point of the liquid would bemore than its normal boiling point.