The Concentration of a Solution is defined as the relative amount of solute present in a solution.
Methods of Expressing Concentration of Solutions are as given below –
1. Percentage by weight :-
Symbol: (W / W %)
Definition: “It is the amount of solute present in 100 g of solution”.
Formula :- Weight Percent (W/W) = Weight of solute/Weight of solution x 100
Unit: unitless.
2. Percentage by volume :-
Symbol: (V / V %)
Definition: “It is defined as the volume of solute present in 100 mL of solution”.
Formula :- Volume Percent (V/V) = Volume of solute/Volume of solution x 100
Unit: unitless
3. Weight by volume :-
Symbol: (W / V %)
Definition: “It is defined as the amount of solute present in 100 mL of solution”.
Formula :- Weight/ Volume Percent (W/V) = Weight of solute (g)/Volume of solution x 100
Unit: g/L
4. Mole fraction :-
Symbol: ( X )
Definition: “It is the ratio of the number of moles of solute and the total number of moles of solute and solvent”.
Formula :- X sloute = Moles of solute/Total moles of all components
Unit: unitless
5. Parts per million:-
Symbol: ppm
Definition: “It is defined as the parts of a component per million parts ( ) of the solution. It is widely used when a solute is present in trace quantities”.
Formula :-
Unit: ppm
6. Molarity :-
Symbol: M
Definition: “Molarity of any solution is the number of moles of solute per litre of solution”.
Formula :- Molarity = moles of solute (mol)/Volume of solution (L)
Unit: mol/L
7. Molality :-
Symbol: m
Definition: “Molality of any solution is represented as the number of moles of solute present per kg of solvent”.
Formula :- Molality = moles of solute (mol)/Weight of solvent (kg)
Unit: mol/kg
8. Normality :-
Symbol: N
Definition: “It is defined as the gram equivalent weight per litre of solution”.
Formula :- Normality = mass of solute (g)/Eqivalent mass x Volume of solution (L)
Unit: gram equivalent/ L.
Concentration is basically a measure to find the amount of solute present in a solvent which together forms a solution.
