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The reaction with hydrochloric acid is an equilibrium reaction that favors formation of tetrachloroaurate(III) anions. This results in a removal of gold ions from solution and allows further oxidation of gold to take place. The gold dissolves to become chloroauric acid. In addition, gold may be dissolved by the chlorine present in aqua regia ...
Gold is unaffected by most acids. It does not react with hydrofluoric, hydrochloric, hydrobromic, hydriodic, sulfuric, or nitric acid. It does react with selenic acid, and is dissolved by aqua regia, a 1:3 mixture of nitric acid and hydrochloric acid. Nitric acid oxidizes the metal to +3 ions, but only in minute amounts, typically undetectable ...
Acid test. An acid test is a qualitative chemical or metallurgical assay utilizing acid. Historically, it often involved the use of a robust acid to distinguish gold from base metals. Figuratively, the term represents any definitive test for attributes, such as gauging a person's character or evaluating a product's performance.
Gold is insoluble in nitric acid alone, which dissolves silver and base metals, a property long used to refine gold and confirm the presence of gold in metallic substances, giving rise to the term ' acid test '. Gold dissolves in alkaline solutions of cyanide, which are used in mining and electroplating.
It is an electrolytic process using pure gold for the cathode (or titanium as a starter cathode) and chloroauric acid (gold chloride-hydrochloric acid) as the electrolyte; this is made by dissolving gold with chlorine gas in the presence of hydrochloric acid. Gold is dissolved at the anode, and pure gold, traveling through the acid by ion ...
Nitratoauric acid, hydrogen tetranitratoaurate, or simply called gold(III) nitrate is a crystalline gold compound that forms the trihydrate, HAu(NO 3) 4 ·3H 2 O or more correctly H 5 O 2 Au(NO 3) 4 ·H 2 O. [3] [2] This compound is an intermediate in the process of extracting gold. [4] In older literature it is also known as aurinitric acid. [5]
Nitric acid is an inorganic compound with the formula H N O 3. It is a highly corrosive mineral acid. [ 6 ] The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water.
Like all metals, gold is insoluble in a water. Gold does however exhibit the distinctive properties that in the presence of cyanide ions, it dissolves in the presence of oxygen (or air). This transformation was reported in 1783 by Carl Wilhelm Scheele, but it was not until the late 19th century, that the reactions were exploited commercially.