Dropping funnel

  A dropping funnel is a type of laboratory glassware used to transfer fluids. They are fitted with a stopcock which allows the flow of to be controlled. Dropping funnels are useful for adding reagents slowly, i.e. drop-wise. This may be desirable when the quick addition of the reagent may result in side reactions, or if the reaction is too vigorous.

Additional recommended knowledge

Don't let static charges disrupt your weighing accuracy

Recognize and detect the effects of electrostatic charges on your balance

Daily Visual Balance Check

Pressure-equalizing dropping funnels have a ground glass joint surrounding the stem, allowing the dropping funnel to be fitted directly to the receiver such as a round bottom flask. If the receiver did not have another opening, the flow of fluid will rapidly come to a halt due to the built-up pressure. Thus, a narrow-bore glass tube is connected from the joint to the top of the dropping funnel to allow the overpressure to be relieved.

See also

• Separatory funnels are similar in shape and design, and may be used as dropping funnels. They do not have the ground glass joint at the stem.