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  2. Aqua regia - Wikipedia

    en.wikipedia.org/wiki/Aqua_regia

    Nitric acid is a powerful oxidizer, which will dissolve a very small quantity of gold, forming gold(III) ions (Au 3+). The hydrochloric acid provides a ready supply of chloride ions (Cl −), which react with the gold ions to produce tetrachloroaurate(III) anions ([AuCl 4] −), also in solution. The reaction with hydrochloric acid is an ...

  3. Gold parting - Wikipedia

    en.wikipedia.org/wiki/Gold_parting

    Nitric acid, after distillation to increase the acid strength, is capable of dissolving the silver but it will not (by itself) dissolve the gold. However, nitric acid is not able to (fully) extract silver and other impurities from an alloy with a high content of gold. Therefore, one part of scrap gold was typically alloyed with three parts of ...

  4. Hydrochloric acid - Wikipedia

    en.wikipedia.org/wiki/Hydrochloric_acid

    Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid. It is a component of the gastric acid in the digestive systems of most animal species, including humans.

  5. List of alchemical substances - Wikipedia

    en.wikipedia.org/wiki/List_of_alchemical_substances

    Fulminating silver – principally, silver nitride, formed by dissolving silver(I) oxide in ammonia. Very explosive when dry. Fulminating gold – a number of gold based explosives which "fulminate", or detonate easily. – gold hydrazide, formed by adding ammonia to the auric hydroxide. When dry, can explode on concussion.

  6. Piranha solution - Wikipedia

    en.wikipedia.org/wiki/Piranha_solution

    Molecular models of the different molecules active in Piranha solution: peroxysulfuric acid (H 2 SO 5) and hydrogen peroxide (H 2 O 2). Piranha solution, also known as piranha etch, is a mixture of sulfuric acid (H 2 SO 4) and hydrogen peroxide (H 2 O 2).

  7. Metal ions in aqueous solution - Wikipedia

    en.wikipedia.org/wiki/Metal_ions_in_aqueous_solution

    A metal ion in aqueous solution or aqua ion is a cation, dissolved in water, of chemical formula [M(H 2 O) n] z+.The solvation number, n, determined by a variety of experimental methods is 4 for Li + and Be 2+ and 6 for most elements in periods 3 and 4 of the periodic table.

  8. Flux (metallurgy) - Wikipedia

    en.wikipedia.org/wiki/Flux_(metallurgy)

    A mixture of organic acids (resin acids, predominantly abietic acid, with pimaric acid, isopimaric acid, neoabietic acid, dihydroabietic acid, and dehydroabietic acid), rosin is a glassy solid, virtually nonreactive and noncorrosive at normal temperature, but liquid, ionic and mildly reactive to metal oxides at molten state. Rosin tends to ...

  9. Pickling (metal) - Wikipedia

    en.wikipedia.org/wiki/Pickling_(metal)

    Most copper alloys are pickled in dilute sulfuric acid, but brass is pickled in concentrated sulfuric and nitric acid mixed with sodium chloride and soot. [ 1 ] In jewelry making , pickling is used to remove the copper oxide layer that results from heating copper and sterling silver during soldering and annealing.