Gold parting will not dissolve gold, nearly pure gold (very close to 99.5% pure) will be left behind after the reaction is complete. After removing the solid gold other elements like silver and copper may be extracted from the liquid. To get the gold to a very high level of purity (999 fine gold) it is sometimes processed further with aqua regia to effectively remove all the impurities. 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
Formic acid carboxylic acids. Because of its high acidity, solutions in alcohols form esters spontaneously. Formic acid shares some of the reducing properties of aldehydes, reducing solutions of gold, silver, and platinum to the metals. Heat and especially acids cause formic acid to decompose to carbon monoxide (CO) and water (dehydration). Treatment of formic acid with sulfuric acid is a convenient laboratory source of CO. In the presence of platinum, it decomposes with a release of hydrogen and carbon dioxide. Soluble ruthenium catalysts are also effective. Carbon monoxide free hydrogen has been generated in a very wide pressure range (1–600 bar). Formic