Bredig's arc method or electrical disintegration is a method of preparation of colloidal solution, of metals such as

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

platinum Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name origina ...

. This method consists of both dispersion and

condensation Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor ...

. An arc is struck between

electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a varie ...

s of the desired metal, under the surface of water containing some stabilizing agent such as traces of

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

. The intense heat of the arc vaporizes some of the metal which then condenses under cold water. The water is kept cold with an ice bath. This method is not suitable when the dispersion medium is an organic liquid as considerable

charring Charring is a chemical process of incomplete combustion of certain solids when subjected to high heat. Heat distillation removes water vapour and volatile organic compounds (syngas) from the matrix. The residual black carbon material is Char (chemi ...

occurs.

References

* {{cite book , last=Books , first=V. , title=INTERMEDIATE II YEAR CHEMISTRY(English Medium) TEST PAPERS: Model papers, Practice papers, Important Questions , publisher=Vikram Publishers Pvt Ltd , url=https://books.google.com/books?id=ApQTBQAAQBAJ&pg=PA103 , language=ca , access-date=2021-04-30 Colloids