Dropping funnel

Note the stopcock, glass tube at the right, and ground glass joint in this pressure-equalizing dropping funnel. An ordinary dropping funnel lacks the pressure-equalizing glass tube at the right side.

A dropping funnel or addition funnel is a type of laboratory glassware used to transfer liquids. They are fitted with a stopcock which allows the flow to be controlled. Dropping funnels are useful for adding reagents slowly, i.e. drop-wise. This is desirable when the quick addition of the reagent results in side reactions, or if the reaction is too vigorous.[1]

Dropping funnels are usually constructed with a ground glass joint at the bottom, which allows the funnel to fit snugly onto a round bottom flask. This also means it need not be clamped separately.[1]

Dropping funnels have been in use since at least the mid-1800s.[2]

  1. ^ a b Zubrick, James W. (2020). The organic chem lab survival manual: a student's guide to techniques (11th ed.). Hoboken, NJ: Wiley. ISBN 978-1-119-60855-4.
  2. ^ Schindler, Hans (November 1, 1957). "Notes on the history of the separatory funnel". Journal of Chemical Education. 34 (11): 528. doi:10.1021/ed034p528. ISSN 0021-9584.