Explain molarity and molality in short.

Explanation

Molarity : Molarity (M) is defined as number of moles of solute dissolved in one litre (or one cubic decimeter) of solution.
Molarity `=("Molaes of solute")/("Volume of solution in litre")`
For example : `0.25 mol L^(-1)` (or 0.25 M) solution of NaOH means that 0.25 mol of NaOH has been dissolved in one litre (or one cubic decimeter).
Molality : Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the solvent and is expressed as :
Molality `(m)=("Moles of solute")/("Mass oif solvent in kg")`
For example : 1.00 mol `kg^(-1)` (or 1.00 m) solution of KCl means that 1 mol (74.5 g) of KCl is dissolved in 1 k of water. Each method of expressing concentration of the solutions has it sown merits and demerits. Mass % ppm, mole fraction and molality are independent of temperature, whereas not only molarity but also %w/V, %V/V and normality are temperature. Dependant this is because volume depends on temperature and the mass does not.