Question

The unit of molality is:
A. Mol/L
B. L/mol
C. Mol/Kg
D. K

Answer 1

The concentration of the solution is determined by various factors like mass concentration, molality, volume concentration. The molality of the solution is defined as the number of moles of solutes dissolved in mass of solvent.

Complete step by step answer:
The concentration is defined as the abundance of constituent particles divided by the total volume of the solution.
The concentration can be distinguished into different mathematical descriptions: mass concentration, molar centration, molal concentration, volume concentration.
The solution is formed by dissolving solute into solvent. The molality is the measure of solute particles dissolved in the solution.
The molality of the solution is defined as the number of solute dissolved in one kilogram of solvent. The molality of the solution is also known as a molal solution. When one mole of solute is dissolved in one kilogram of solvent then one molal solution is formed. The molality is expressed in terms mol per kg. The unit of molality is $molk{g^{ - 1}}$. The molality is denoted by “m”
The formula to calculate the molality is shown below.
$m = \dfrac{n}{{M\;in\;kg}}$
m is the molality of the solution
n is the number of moles
M is the mass of solvent in kilogram
To calculate the molality of the solution, we need to find the number of moles when mass of the compound is given. The moles can be calculated by dividing the mass of the compound with the molecular weight of the compound.
Thus, the unit molality is mol/kg.
Therefore, the correct option is C.

Note:
The molarity of the solution is also the concentration of solution which is calculated in terms of mole per litre. Molarity is defined as the number of moles dissolved in one liter solution. The unit of molarity is mol/L. The molarity is denoted by “M”.