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Discussion

Designed for Classical Quantitative Volumetric Analysis

Solid from Dish to Flask and the alternative Solid from Dish to Beaker to Flask illustrate two procedures for quantitatively transferring a solid to a volumetric flask. Transfer to a beaker is used when the solid is difficult to dissolve and stirring is required to aid dissolution. If the solid dissolves easily, it is transferred directly from the weighing dish to a volumetric flask.

It is critical that the inner walls of the volumetric flask be checked for quantitative drainage before the solid is transferred to the flask. Local volumetric flask inner wall cleaning procedures should be used to insure the upper inner wall of the flask drains quantitatively “droplet free”

Narrative

We have an accurately weighed solid sample in the weighing dish that we want to quantitatively transfer to a 250 mL volumetric flask. We will dilute to the mark with deionized water.

First, we check our flask to see that it is quantitatively clean. The inner wall above the dilution mark is the region of greatest interest. We rinse it with deionized water, allow it to drain and then hold the flask up to eye level to see if any droplets adhere to the inner wall. Deionized water droplets adhering below the mark are not a problem assuming they are deionized water. They will simply become part of the solution.