Question

Difference between normal and standard boiling point of water

Answer 1

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.

Answer 2

Explanation:

• Normal boiling point is defined as the temperature in which a liquid like water starts to change from liquid into vapor state at 1 atm pressure.

The normal boiling point of water is $99.97^{o}C$ at 1 atm.

• On the other hand, standard boiling point is defined as the temperature at which a liquid like water starts to change from liquid into vapor state at a pressure of 1 bar.

The standard boiling point of water at 1 bar is $99.61^{o}C$.