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Because of the explosion hazard related to hydrogen produced by the reaction of aluminium with hydrochloric acid, the most common industrial practice is to prepare a solution of aluminium chlorohydrate (ACH) by reacting aluminium hydroxide with hydrochloric acid. The ACH product is reacted with aluminium ingots at 100 °C using steam in an open ...
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 equilibrium reaction that favors formation of tetrachloroaurate(III) anions.
Hydrated aluminium trichloride is prepared by dissolving aluminium oxides in hydrochloric acid. Metallic aluminium also readily dissolves in hydrochloric acid ─ releasing hydrogen gas and generating considerable heat. Heating this solid does not produce anhydrous aluminium trichloride, the hexahydrate decomposes to aluminium hydroxide when ...
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).
A solution of zinc chloride in hydrochloric acid is a common flux for stainless steels; it has however to be thoroughly removed afterwards as it would cause pitting corrosion. Another highly effective flux is phosphoric acid; its tendency to polymerize at higher temperatures however limits its applications.
Aqua regia was also used for parting. It was made by adding sal ammoniac to nitric acid which produced a mixture of hydrochloric acid and nitric acid. This acid dissolved the gold to a soluble chloride and the silver was attacked and precipitated as an insoluble chloride. Silver was removed by filtering and gold was then recovered by ...
In hot concentrated hydrochloric acid, aluminium reacts with water with evolution of hydrogen, and in aqueous sodium hydroxide or potassium hydroxide at room temperature to form aluminates—protective passivation under these conditions is negligible. [47] Aqua regia also dissolves aluminium. [46]
[citation needed] The reaction progress is not dependent on solvent or substrate. A widely accepted mechanism involves a carbocation intermediate. The Fries rearrangement. In the first reaction step a Lewis acid for instance aluminium chloride AlCl 3 co-ordinates to the carbonyl oxygen atom of the acyl group.