Answer: Option (c) is the correct answer.
Explanation:
Boiling point is defined as the point at which vapor pressure of a liquid becomes equal to the atmospheric pressure.
Boiling point of water is [tex]100^{o}C[/tex].
Whereas when we heat one mole of a liquid at its boiling point without any change in temperature then the heat required to bring out change from liquid to vapor state is known as heat of vaporization.
Thus, we can conclude that the heat of vaporization of water is the amount of heat/energy required to convert 1 gram of liquid water at [tex]100^{o}C[/tex] to 1 gram of steam at [tex]100^{o}C[/tex].