<P> The normal boiling point ( also called the atmospheric boiling point or the atmospheric pressure boiling point ) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level , 1 atmosphere . At that temperature , the vapor pressure of the liquid becomes sufficient to overcome atmospheric pressure and allow bubbles of vapor to form inside the bulk of the liquid . The standard boiling point has been defined by IUPAC since 1982 as the temperature at which boiling occurs under a pressure of 1 bar . </P>
<P> The normal boiling point ( also called the atmospheric boiling point or the atmospheric pressure boiling point ) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level , 1 atmosphere . At that temperature , the vapor pressure of the liquid becomes sufficient to overcome atmospheric pressure and allow bubbles of vapor to form inside the bulk of the liquid . The standard boiling point has been defined by IUPAC since 1982 as the temperature at which boiling occurs under a pressure of 1 bar . </P>
the normal boiling point of any substance would occur at
the normal boiling point of any substance would occur at
sea level
sea level