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 with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile ...

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

platinum Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Pla ...

. This method consists of both

dispersion Dispersion may refer to: Economics and finance *Dispersion (finance), a measure for the statistical distribution of portfolio returns *Price dispersion, a variation in prices across sellers of the same item *Wage dispersion, the amount of variatio ...

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 vapo ...

. 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 air). Electrodes are essential parts of batteries that can consist of a variety of materials ...

s of the desired metal, under the surface of water containing some

stabilizing agent In industrial chemistry, a stabilizer or stabiliser is a chemical that is used to prevent degradation. File:BigPhosphite31570-04-4.png, Tris(2,4-di-tert-butylphenyl)phosphite is a widely used stabilizer in polymers. File:HALSgeneric.png, Partial ...

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 exp ...

. 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 Interface and colloid science is an interdisciplinary intersection of branches of chemistry, physics, nanoscience and other fields dealing with colloids, heterogeneous systems consisting of a mechanical mixture of particles between 1 nm ...

is an

organic liquid In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The st ...

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, as d ...

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