Kipp's apparatus, also called Kipp generator, is an apparatus designed for preparation of small volumes of gas

Gas

Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...

es. It was invented around 1860 by the Dutch pharmacist Petrus Jacobus Kipp

Petrus Jacobus Kipp

Petrus Jacobus Kipp was a Dutch apothecary, chemist and instrument maker. He became known as the inventor of the Kipp apparatus, chemistry equipment for the development of gases.-Biography:...

 and widely used in chemical laboratories and for demonstrations in schools into the second half of the 20th century.

It later fell out of use, at least in laboratories, because most gases then became available in small gas cylinder

Gas cylinder

A gas cylinder is a pressure vessel used to store gases at above atmospheric pressure. High pressure gas cylinders are also called bottles. Although they are sometimes colloquially called "tanks", this is technically incorrect, as a tank is a vessel used to store liquids at ambient pressure and...

s. These industrial gases are much purer and drier than those initially obtained from a Kipp apparatus without further processing.

Design and operation

The apparatus is made of three vertically stacked cylinders, roughly resembling a snowman. The solid material (e.g., 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 only work properly in the described manner if the solid material is insoluble in the acid. They are usually made of glass

Glass

Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

, or sometimes of polyethylene

Polyethylene

Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...

.

Examples for prepared gases and their educts

• Hydrogen
  Hydrogen
  Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
  
   from zinc
  Zinc
  Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
  
   flakes and hydrochloric acid
  Hydrochloric acid
  Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
  
  
• Carbon dioxide
  Carbon dioxide
  Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
  
   from pieces of marble
  Marble
  Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...
  
   (calcium carbonate
  Calcium carbonate
  Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
  
  ) and hydrochloric acid
• Hydrogen sulfide
  Hydrogen sulfide
  Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
  
   from iron(II) sulfide
  Iron(II) sulfide
  Iron sulfide or ferrous sulfide is a chemical compound with the formula . In practice, iron sulfides are often non-stoichiometric. Powdered iron sulfide is pyrophoric Iron(II) sulfide or ferrous sulfide (Br.E. sulphide) is a chemical compound with the formula . In practice, iron sulfides are...
  
   and hydrochloric acid
• Acetylene
  Acetylene
  Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...
  
   from calcium carbide
  Calcium carbide
  thumb|right|Calcium carbide.Calcium carbide is a chemical compound with the chemical formula of CaC2. The pure material is colorless, however pieces of technical grade calcium carbide are grey or brown and consist of only 80-85% of CaC2 . Because of presence of PH3, NH3, and H2S it has a...
  
   and water
  Water
  Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
  
  
• Chlorine
  Chlorine
  Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
  
   from potassium permanganate
  Potassium permanganate
  Potassium permanganate is an inorganic chemical compound with the formula KMnO4. It is a salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent. It dissolves in water to give intensely purple solutions, the...
  
   or manganese dioxide and hydrochloric acid

For further reading

• Kipp's apparatus - extensive explanation with pictures and references