Glassware used to make and store solutions of known concentration is:

• A. Volumetric Flask
• B. Beaker
• C. Erlenmeyer Flask
• D. Graduated Cylinder

Answer: (A)

The main idea is using a vessel that defines an exact final volume so you can know the concentration precisely. A volumetric flask is built for this purpose: it has a narrow neck with a single calibration mark that indicates a very specific total volume. If you dissolve a known amount of solute in solvent and dilute up to that mark, the resulting solution has a known concentration. The neck can be stoppered, so the solution can be stored with minimal evaporation or contamination.

Beakers and Erlenmeyer flasks are general-purpose vessels used for mixing, heating, or transferring liquids, but their volumes aren’t precise. A graduated cylinder measures volume with more precision than a beaker or Erlenmeyer, but it doesn’t provide a single fixed final volume for a solution, so it’s not ideal for making standard solutions.