Volumetric flask

A flask used for making up an accurate volume of solution. They are used to make standard solutions. Volumetric flasks come in a wide variety of volumes, but the ones most often met in schools and colleges are 100 cm³, 250 cm³ and 1000 cm³. The flask should be washed out with distilled water before use.

The volume is indicated by a line inscribed into the neck of the flask. As with all other measurements, it is filled so that the bottom of the liquid meniscus just touches the line. This is called making up to the mark. For accurate work, any drops of water above the line should be removed with a rolled up filter paper. The contents need to be thoroughly mixed. Make sure you use a correctly fitting stopper - not your thumb! You can find out more about the accuracy of these flasks in the error section.