(i) Mole fraction: The mole fraction of a component in a mixture is defined as the ratio of the number of moles of the component to the total number of moles of all the components in the mixture.

Mole fraction of a component = \(\frac{Number\;of\;moles\;of\;the\;component}{Total\;number\;of\;moles\;of\;all\;components}\)

Mole fraction is denoted by 'x'.

If in a binary solution, the number of moles of the solute and the solvent are n_A and n_B respectively, then the mole fraction of the solute in the solution is given by,

x_A = \(\frac{n_A}{n_A + n_B}\)

Similarly, the mole fraction of the solvent in the solution is given as,

x_B = \(\frac{n_B}{n_A + n_B}\)

(ii) Molality

Molality (m) is defined as the number of moles of the solute per kilogram of the solvent. It is expressed as,

Molality (m) = \(\frac{Moles\;of\;solute}{Mass\;of\;solvent\;in\;kg}\)

(iii) Molarity

Molarity (M) is defined as the number of moles of the solute dissolved in one Litre of the solution.

It is expressed as,

Molarity (M) = \(\frac{Moles\;of\;solute}{Volume\;of\;solution\;in\;Litre}\)

(iv) Mass percentage

The mass percentage of a component of a solution is defined as the mass of the solute in grams present in 100 g of the solution. It is expressed as

Mass % of a component = \(\frac{Mass\;of\;component\;in\;solution}{Total\;mass\;of\;solution}\) x 100