Kipp's apparatus

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The most commonly known use is for preparation of hydrogen sulfide in qualitative inorganic analysis by reaction of sulfuric acid with ferrous sulfide FeS, carbon dioxide by reaction of hydrochloric acid with calcium carbonate, and hydrogen by reaction of an acid with a suitable metal.

The apparatus is made of three vertically stacked cylinders, roughly resembling a snowman. The solid material (eg. iron sulfide) is placed into the middle cylinder, the acid is put into the top cylinder. A tube extends from the top cylinder into the bottom cylinder. The middle cylinder has a tube with a stopcock attached, which is used to draw off the evolved gas. When the stopcock is closed, the pressure of the gas in the middle cylinder rises and expels the acid back into the top cylinder, until it is not in contact with the solid material anymore, and the chemical reaction stops.

Kipp generators are usually made of glass, or sometimes of polyethylene.

For further reading

* cite book | last = Green| first = John Joseph | title = Chemical Recreations: A Popular Manual of Experimental Chemistry | publisher = John Joseph Green | year = 1860 | edition = 10 | page = 616 | accessdate = 2007-11-12 | url = http://books.google.com/books?id=LgU5AAAAMAAJ&pg=PA616&dq=kipp%27s+apparatus#PPA617,M1

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* [http://mattson.creighton.edu/History_Gas_Chemistry/Kipps.html Kipp's apparatus] - extensive explanation with pictures and references