Question

Define normality . What is relation between normality and molarity of monobasic,dibasic and tribasic acid and monoacidic ,diacidic and triacidic base.

Answer 1

Dear student,
In chemistry, Normality is used to measure concentration of the solution.
​​​​​​Normality is defined as number of gram equivalent in solute present in one litre of solution. It is denoted by 'N'
$\mathrm{N}=\frac{\mathrm{no}.\mathrm{of}\mathrm{gram}\mathrm{equivalent}\mathrm{in}\mathrm{solute}}{\mathrm{volume}\mathrm{of}\mathrm{solution}\left(\mathrm{Litres}\right)}$
whereas, molarity is also used to measure concentration of the solution and is denoted by 'M'
$\mathrm{M}=\frac{\mathrm{no}.\mathrm{of}\mathrm{moles}\mathrm{of}\mathrm{solute}}{\mathrm{volume}\mathrm{of}\mathrm{solution}\left(\mathrm{Litres}\right)}$
there is a relation between molarity and normality which is given by,
$\mathrm{N}=\mathrm{n}-\mathrm{factor}\times \mathrm{M}$
this n-factor for acids is its basicity, i.e. no of replaceable hydrogen ion per molecule and for a base is its acidity i.e. number of replaceable OH^- ion per molecule of base.
So, the relation between Normality and Molarity for different base and acid is as follow:
$\frac{\mathrm{N}}{\mathrm{M}}=\mathrm{n}-\mathrm{factor}$
for monobasic acid and monoacid base =1
for dibasic acid and diacidic base =2
for tribasic acid and triacidic base=3
Regards.