What piece of glassware should be used for preparing 100ml of a standard?

The volumetric flask is the appropriate choice for preparing 100 ml of a standard because it is specifically designed for making precise dilutions and solutions. Volumetric flasks have a single calibrated line that indicates the exact volume, ensuring that the liquid inside is exactly at the intended measurement when filled to that line. This precision is crucial in analytical chemistry and laboratory settings, where accurate concentrations are necessary for reliable results.

In contrast, a graduated cylinder, while useful for measuring liquids, has a broader range of measurement and is not as precise as a volumetric flask for preparing standards. Pipets are designed for transferring specific volumes of liquid but are not suitable for preparing solutions from scratch. Erlenmeyer flasks, on the other hand, are typically used for mixing and heating solutions, but they do not provide the same level of accuracy in volume measurement as volumetric flasks.

Overall, the volumetric flask's design and function make it the best choice for accurately preparing solutions of specific volumes.