Question

How can we prepare $0.1\;N$ $HCl$ Solution?

Answer 1

Hint : We are making $0.1\;N$ solution of hydrochloric acid we should first understand what is normality it is measure of concentration of a solution it is defined as number of gram equivalent or mole equivalent of solute present in one litre of the solution. Normality is used to measure the concentration of acids and bases.

Complete Step By Step Answer:
Normality can be calculated by multiplying the molarity of acid with the number of Hydrogen ions or in case of bases multiplying with the number of hydroxide ions.
For preparing $0.1\;N$ $HCl$ solution we will dilute $0.1\;{\text{M}}$ $37.5\;\%$ concentrated Hydrochloric acid. we need to calculate the normality of this solution by multiplying its molarity with number of Hydrogen ion Since Hydrochloric acid has one hydrogen ion
${\text{N}}\; = \;0.1\; \times \;1$
${\text{N}}\; = \;0.1$
The Normality of the solution is $0.1$ .
The equivalent mass is calculated by dividing the molar mass with the number of hydrogen ions. Since Hydrochloric acid has one hydrogen ion, the mass of hydrochloric acid will remain the same.
Now writing the values
Equivalent mass of Hydrochloric acid, ${\text{M}} = 36.4611\;gmo{l^{ - 1}}$
Volume of the solution, ${\text{V}}\; = \;1\;Litre$
Normality of the solution, ${\text{N}}\; = \;0.1$
Specific gravity of Hydrochloric acid $Specific\;Gravity\; = \;1.189$
For calculating the weight of compound needed put the values in formula we get
${\text{w}}\; = \;0.1\; \times \;36.4611\; \times \;1$
${\text{w}}\; = \;3.6461\;{\text{g}}$
Now calculating volume of the concentrated Hydrochloric acid needed to prepare the desired solution
${\text{V}}\; = \;\dfrac{{3.6461}}{{0.375 \times 1.189}}$
${\text{V}}\; = \;8.1774\;mL$
So, $8.1774\;mL$ of $37.5\;\%$ concentrated Hydrochloric acid is needed to prepare the $0.1\;N$ $HCl$ solution.

Note :
Specific gravity is calculated by dividing the density of a substance with a density of reference substance. It can also be called relative density. Carefully do the calculation and remember the unit of each variable you are using.