Question

Which one of the following is an extensive property
A . Molar Volume
B . Molarity
C . Number of moles
D . Mole Fraction

Answer 1

Hint: In this question we have to use the concept of extensive property. An extensive property is a property of matter that is dependent on the quantity of the substance. As the amount of matter or sample changes, the extensive properties alter.
An intense property is a characteristic of matter that is independent of the quantity of the substance.

Complete answer:Molar volume is inversely proportional to density and directly proportional to molar mass. The molar volume formula is expressed as:
${{V}_{m}}=\dfrac{molar\text{ }mass}{density}$
Molar volume does not change as the amount of matter changes.
Thus, Molar volume is an intensive property

The number of moles of solute present in a specific number of litres of the solution, or moles per litre of a solution, is known as molar concentration or molarity. It is one of the most often used concentration units and is represented by the letter M.
 The formula for it is:
$Molarity=\dfrac{moles\text{ }of\text{ }solute}{volume\text{ }of\text{ }solution\text{ }in\text{ }litres}$
Molarity is an intensive property as it is independent of the quantity of the substance.

A mole is the mass of a substance made up of the same number of fundamental components. Atoms in a 12-gram example are identical to 12C. Depending on the substance, the fundamental units may be molecules, atoms, or formula units.
A mole fraction shows how many chemical elements are present. The value of 6.023 x 1023 (Avagadro number) is equal to one mole of any substance.
\[Number\text{ }of\text{ }moles=\dfrac{mass\text{ }of\text{ }substance}{mass\text{ }of\text{ }one\text{ }mole}\]
The number of moles is whose magnitude depends upon the amount of matter, thus it is an extensive property.

The ratio of the number of moles of one component of a solution to the total number of moles of all of the components in the solution is called the mole fraction. The sum of mole fractions of all the components of a solution is always equal to 1.
Therefore, mole fraction is an intensive property.

The correct answer is C.

Note: An extensive property of matter is one that is impacted by any change in the substance, as opposed to an intensive property of matter, which remains constant regardless of how the material is altered. Mass, volume, and the number of moles are all extensive properties as they all depend on the mass or amount.