It consists in adding more pure solvent to a given solution.

The mass of a solution after being diluted remains unchanged, but its concentration and volume change. As the volume increases, the concentration decreases. See the formula:

Where:

M_{1} = molarity of solution 1

M_{2} = molarity of solution 2

V_{1} = volume of solution 1

V_{2} = volume of solution 2

For this formula, always M_{1} and V_{1} are more concentrated and M_{2} and V_{2} are more diluted.

Example:

A chemist wants to prepare 1500mL of a 1.4mol / L hydrochloric acid (HCl) solution by diluting a 2.8mol / L solution of the same acid. How much solution was in the first solution to be diluted? Dice:

Note that the volume units were kept in mL. If one of the units is different, it must be transformed to liters.