Question

Which of the following is not an extensive property?
(A) molarity
(B) heat capacity
(C) mass

Answer 1

Hint : Extensive and Intensive properties are come under the category of macroscopic properties of thermodynamics. Extensive properties in thermodynamics is defined as "the properties of any system which directly or indirectly dependent on the amount or mass or size of system is
known as extensive properties".

Complete Step By Step Answer:
(i) Molarity of solution is defined as moles of solute dissolved per litre of solution system.
on changing the value of volume of solution, molarity of solution also varies.
molarity of solution remains independent of mass or amount of solute present in solution
$M = \dfrac{n}{V}$
Where, $M$ is molarity of solution
$n$ Is number of moles of solute present
$V$ Is volume of solution in litre
(ii) During chemical reactions, systems either absorb the energy or release the energy. Hence, the heat capacity of a chemical reaction is defined as "amount of heat needed in order to raise the temperature of the reaction system by one degree".
$Q = mc\Delta {\rm T}$
Where, $Q$ i s heat energy
$m$ Is mass of substance
$c$ Is specific heat capacity
$\Delta {\rm T}$ Change in temperature during reaction
From the above definition we see that the value of heat capacity varies with the change in amount of matter.
(iii) Mass of the system represents the quantitative value of substance present in the system.
From the above discussion, we see that heat capacity and mass both these properties depend upon the amount or mass of the system. Hence, they are extensive property.
Molarity is remaining nondependent to amount or mass of the system and hence this is not an example of extensive properties.

Note :
Extensive properties are additive in nature while this property is not found in intensive property.
System which remain independent to the value of mass or amount or size of system is known as intensive system. Ratio of two extensive properties leads to formation of intensive property.