Are volumetric flasks more commonly calibrated at To Deliver (TD) or To Contain (TC)?

Volumetric flasks are designed and calibrated specifically to contain a precise volume of liquid when filled to a marked line on the neck of the flask. This characteristic is vital for ensuring accuracy in volumetric measurements, particularly in laboratory settings where exact quantities are essential for experiments or analytical procedures.

When a volumetric flask is filled to the specified mark, it holds the intended volume, which is what "To Contain" signifies. This means the flask will accurately deliver the volume of liquid that it is designed for without accounting for any liquid that may adhere to the walls of the flask during transfer. As a result, volumetric flasks are not suitable for use in applications requiring precise volumes to be dispensed, as they are intended for storage and measurement of liquids rather than precise delivery.

In contrast, other types of laboratory glassware may be calibrated "To Deliver," which would indicate that they are designed for dispensing the exact volume indicated. Since volumetric flasks specifically do not provide for this type of usage, the choice of "To Contain" is appropriate for their calibration.