Class B volumetric glass ware provides the highest accuracy and passes the ASTM standard specification for laboratory volumetric glass ware.

• A. True
• B. False
• C. Not sure
• D. Sometimes

Answer: (B)

Accuracy in volumetric glassware is defined by how tightly the actual volume can deviate from the marked volume, which is set by the class designation. Class A pieces have the tightest tolerances and are usually certified to show they meet precise volumes at 20°C, making them the highest-accuracy option for quantitative work. Class B, by contrast, has looser tolerances and is intended for general laboratory use where extreme precision isn’t required. Both classes are governed by ASTM standards that specify the tolerances for each class, but only Class A provides the highest level of accuracy. Therefore, the statement is not correct. For precise measurements, choose Class A, and keep in mind that temperature affects volume since these marks are defined at a standard temperature (often 20°C), so corrections may be needed if you’re operating at a different temperature.