Question

The boiling of water in Kelvin scale is:
A. $73.15K$
B. $173.15K$
C. $273.15K$
D. $373.15K$

Answer 1

Hint: The Kelvin scale is called absolute scale. Below $0K$ nothing is believed to exist. We know that water boils at ${100^0}C$ . We need to convert this temperature into Kelvin scale value. The relation between Kelvin scale and Centigrade scale is: $Kelvin{ = ^0}Celsius + 273.15$

Complete answer:
First let us understand the concept of boiling point. The point at which the pressure exerted by the surrounding on a liquid is equal to the atmospheric pressure is known as the boiling point of a liquid. In simple terms, the temperature at which liquid is converted to vapour before the temperature rises is termed as the boiling point of the liquid. As the temperature increases, the vapour pressure exerted to the liquid also increases. The boiling points of liquid can be measured in many scales, Kelvin as well as Celsius scale or Fahrenheit scale.

The boiling point of water in Celsius scale is ${100^0}C$ .To convert this Centigrade value into Kelvin value, we will use the following formula:
$Kelvin{ = ^0}Celsius + 273.15$
$ \Rightarrow Kelvin = 100 + 273.15$
$ \therefore Kelvin = 373.15$
Therefore, the boiling point of water in Kelvin scale is $373.15K$

Thus, option D is the correct option.

Note:The relation between Kelvin scale and Fahrenheit scale is important in problem solving. The Kelvin scale is an absolute scale and nothing can exist below the temperature of $0K$. For calculation purposes, we consider Kelvin scale.According to the Fahrenheit scale the boiling point of water is ${212^0}F$ and the freezing point of water is ${32^0}F$ . For the Kelvin scale, the freezing point is $273.15K$ .