Question

The latent heat of vaporization of water is:
A.\[2.25 \times {10^6}{\text{J}}/{\text{kg}}\]
B.\[2.25 \times {10^8}{\text{J}}/{\text{kg}}\]
C.\[2.25 \times {10^4}{\text{J}}/{\text{kg}}\]
D.\[2.25 \times {10^{ - 6}}{\text{J}}/{\text{kg}}\]

Answer 1

Hint:The latent heat of conversion is specific for a particular process. Vaporisation is the process of conversion of liquid into its vapour.

Complete step by step answer:
Heat is a form of energy. The unit of heat is J (joule), it is also measured in calories. Heat can be felt by its effects such as change in degree of hotness, expansion in length, change in state of substance, change in resistance of conductor and etc. Different types of heat are as follows:
Specific heat is defined as the amount of energy which is required to increase the temperature of unit mass of a substance by 1 Kelvin or 1 degree Celsius. Specific heat of water is \[1{\text{ calorie}}/{\text{g }}^\circ {\text{C or }}4200{\text{ joule}}/{\text{KgK}}\]
Molar specific heat is defined as the amount of energy required to increase the temperature of one mole of a substance by 1 Kelvin or 1 degree Celsius.
Heat capacity is the amount of heat required to increase the temperature of any substance by 1 Kelvin or 1 degree Celsius.
Latent heat is defined as the amount of heat absorbed or released during its change of state.
\[{\text{Q}} = {\text{mL}}\]
Where Q is heat involved, m is mass of substance and L is latent heat defined for unit mass of substance. Heat is absorbed if solid converts into liquid or liquid to vapour.
Latent heat of vaporization is the amount of heat required to change 1 Kg mass of liquid to its vapour state. Latent heat of vaporization for water is \[2.25 \times {10^6}{\text{J}}/{\text{kg}}\]

Thus, the correct option is A.

Note:
When the state of matter changes, it takes place at constant temperature. 1 calorie is equivalent to \[4.18\] joule of energy. Heat is released if vapour converts to liquid and liquid to solid. Latent heat of fusion is the amount of heat required to change 1 kilogram of a substance from solid to liquid state.