Mole fraction:
It is the ratio of number of moles of a particular component of a solution to the total number of moles of the solution.
If a substance ‘A’ dissolves in substance ‘B’ and their number of moles are nA and nB , repsectively, then the mole fraction of A and B are given as :
\(Mole \ fraction \ of \ A=\frac{
No.\ of \ moles\ of\ A}{
No.\ of\ moles\ of\ solution}\)
⇒\(n_A\over n_A+n_ B\)
\(
Mole \ fraction \ of \ B =
\frac{Number \ of \ moles \ of\ B}{
Number\ of\ moles\ of\ solution}\)
⇒\(n_B\over n_A+n_ B\)
Molarity:
Molarity is defined as the number of moles of the solute present in 1 litre of the solution. It is the most widely used unit and is denoted by M. Molarity is expressed as follows:
\(
Molarity \ (M) =\frac{
Number\ of\ moles\ of\ solute}{
Volume \ of\ solution\ in \ litres}\)
Molality:
Molality the number of moles of solute present in 1 kg of solvent. It is denoted by m. Molality is expressed as follows:
\( Molality
\ (m) = \frac{Number\ of\ moles\ of\ solute }{Mass \ of \ solvent \ in \ kilograms}\)
