To determine the specific gravity of a liquid, which of the following glass wares should be used?

• A. Volumetric Flask
• B. Pycnometer
• C. Pipette
• D. Graduated Cylinder

Answer: (B)

To determine specific gravity, you’re measuring how dense a liquid is compared with water at the same temperature, which means you need a known, fixed volume and a precise way to weigh that volume of liquid. A pycnometer is built for this purpose: it has a precisely calibrated internal volume and is designed to be weighed with the liquid inside, after ensuring no air bubbles. By weighing the empty pycnometer and then the filled one, you get the mass of a known volume of liquid. density = mass of liquid / known volume. Then you compare that density to the density of water at the reference temperature to get the specific gravity (SG = ρ_liquid / ρ_water). The other glassware isn’t ideal for this direct density determination: a volumetric flask is great for preparing exact solution volumes but not as precise for measuring the liquid’s mass in a fixed volume; a graduated cylinder and a pipette are suited for transferring or measuring approximate volumes rather than providing a calibrated, fixed-volume container for accurate density calculations.