A volumetric flask is a piece of laboratory glassware calibrated to contain a single, highly precise volume of liquid at a specific temperature. It features a bulbous body and a long, narrow neck with a single etched line called a graduation mark (or meniscus mark) to indicate the exact fill level

Key UsesPreparing standard solutions: Dissolving a precise mass of solute into a specific total volume of solvent.Diluting concentrations: Accurately diluting a concentrated stock solution to a precise lower concentration.
Standard Sizes and Accuracy ClassesVolumetric flasks range in size from 1 mL to 10,000 mL. They are generally categorized into two accuracy grades:
Class A: The highest precision standard, used in analytical chemistry. They feature the lowest error tolerances and are often made of thermal-shock-resistant borosilicate glass.Class B: Lower precision with twice the error tolerance of Class A. These are typically used for general educational or qualitative laboratory work.