Boiling Point. The boiling point is defined as the temperature at which the saturated vapor pressure of a liquid is equal to the surrounding atmospheric pressure. read more
( 1 ) When vapor pressure equals the atmospheric pressure, boiling may commence. As you heat a liquid its vapor pressure increases until the vapor pressure equals the atmospheric pressure. Additional heating does not increase temperature , but is used to convert liquid molecules to vapor molecules. read more
As you ascend, atmospheric pressure decreases. In doing so, vapor pressure reaches atmospheric pressure earlier and a liquid will boil at a lower temperature. read more