Question

The molarity of $KMn{{O}_{4}}~$ solution used is:
A. $0.02M$
B. $0.01M$
C. $0.03M$
D. $0.04M$

Answer 1

Morality of a solution can be determined if the normality of the solution is known to us. Normality is an instrument or method to determine the concentration of a solution.

Complete step by step answer:
Molarity or molar concentration of a solution demonstrates the concentration of solute in the solution. Molarity is demonstrating the concentration of solute in the solution. Molarity is defined as the amount of parts of solute in unit volume of the solution.
Molarity is also calculated as the measured number of moles per unit volume that is per litre. The volume for the calculation of molarity must be taken in litres. The SI unit of molarity is $mol/dm{}^\text{3}.$ Molarity is demarcated by M.
Normality refers to the measured number of Gram equivalent of the solute per litre of the solution. Normality is marketed by N. Normality of a solution is also known as its equivalent concentration. Molarity can also be calculated using normality and vice versa. Normality is the molarity’s multiple.
$MnO_{4}^{-}+5F{{e}^{2+}}+8{{H}^{+}}\to 5F{{e}^{3+}}+M{{n}^{2+}}+4{{H}_{2}}O$
$1$ Mole of $KMn{{O}_{4}}~$ corresponds to $5$ equivalents. The normality of $KMn{{O}_{4}}~$solution is $0.1N.$
hence, the molarity of $KMn{{O}_{4}}~$ solution is $\dfrac{0.1}{5}=0.02M$

So, the correct answer is Option A.

Note: Molarity should not be confused with molality. Molality refers to the measured number of solutes in terms of mass of solvent, that is, per kg of solvent. Here n is the number of hydrogen ions in case of acidic medium and the number of Hydroxide ions in case of basic medium.