Which glassware is least precise for measuring liquids?

• A. Beaker
• B. Erlenmeyer flask
• C. Volumetric flask
• D. Graduated cylinder

Answer: (A)

Measuring liquids precisely depends on the instrument’s markings and geometry. A beaker is designed for rough volumes—its graduations are few and imprecise, and the wide mouth makes it easy to read the liquid level at an angle or from an inch out of line, which introduces uncertainty. Because of that, the volume you read from a beaker is only approximate, making it the least precise option among common lab glassware.

In contrast, a graduated cylinder has many fine marks and a narrow shape that helps you read the meniscus more accurately, so it provides a more reliable measurement. A volumetric flask is built for exactness: it has a single calibration mark and is used to prepare precise volumes by filling to that line. An Erlenmeyer flask can be marked as well, and while it can be read with reasonable accuracy, its shape and typical use (mixing, heating) mean it’s not as precise as a graduated cylinder or volumetric flask.