It is a method of volumetric analysis which consists in determining the acid or base concentration through a spent volume of one of the solutions with known molarity.

This method is widely used in chemical laboratories, using the following glassware and reagents:

- erlenmeyer (glass used for storing and preparing solutions);

- burette (glass tube graduated in millimeters with tap);

- acid-base indicator (phenolphthalein, methyl orange, etc.).

In the burette, the known concentration solution is placed, which is added to an aliquot (portion) of the concentration solution to be determined.

The moment the indicator changes color we call the endpoint or equivalence point. Note the volume spent on the burette.

Through this volume we can establish the quantities, in mol, that reacted with each other.