Methods of Expressing the Concentration of a Solution
Methods of Expressing the Concentration of a Solution
The concentration of a solution can be expresses in a number of ways. The important methods are:

Mass/Weight Percentage: (w/W)
It is defined as the amount of solute in grams present in 100 grams of the solution.
Eg, 23% w/W H2SO4 means 23 gm of H2SO4 (solute) in 100 gm of solution.

Volume Percentage (v/V)
It is defined as the volume of solute in mL present in 100 mL solution.
Eg, 23% v/V H2SO4 means 23 ml of H2SO4 (solute) in 100 ml of solution.

Mass Volume Percentage (W/V)
It is s defined as the mass of solute present in 100 mL of solution.
Eg, 23% w/W H2SO4 means 23 gm of H2SO4 (solute) in 100 ml of solution.

Mole Fraction
It is defined as the ratio of the number of moles of that component to the total number of moles of all components.
In a binary solution for 2 components, A and B.

Molarity (M)
Molarity of a solution is the number of gram molecules of the solute present in one litre of the solution.
Units of molarity: mol L1

Molality (m)
It is defined as the number of moles of solute dissolved in 1 Kg of the solvent.
Units of molarity: mol kg1

Normality (N)
It is the number of formula mass in grams present per litre of solution. In case formula mass is equal to molecular mass, formality is equal to molarity. Like molarity and normality, the formality is also dependent on temperature.
Where,

w = weight of solute,

f = formula weight of solute

V= volume of solution

nf = no. of gram formula weight

Formality (F)
It is defined as the number of gram equivalents of the solute present in one litre of the solution.

Parts per million
It is defined as the Number of the parts of components by Total no of parts of all components of the solution per million.