What is a Hirsch Funnel and how are they used?
They are used for vacuum filtration to separate crystals, or solids, from a liquid. Usually a neoprene adapter is used to fit the funnel to a flask that is attached to some sort of vacuum. A filter paper is used to make sure no solids get through, or clog, the funnel. Typically, it is advised, that hot solutions are not used in vacuum filtration because the reduced pressure will cause solvents to evaporate, and the solid will precipitate out; causing the funnel, and pores of the filter paper, to clog.
