![]() On Februin Los Angeles, California, 17 people were killed and 150 injured in the O'Connor Plating Works disaster. Work conducted with perchloric acid must be conducted in fume hoods with a wash-down capability to prevent accumulation of oxidisers in the ductwork. Given its strong oxidizing properties, perchloric acid is subject to extensive regulations as it can react violently with metals and flammable substances such as wood, plastics, and oils. It is also used for electropolishing or etching of aluminium, molybdenum, and other metals. For similar reasons, it is a useful eluent in ion-exchange chromatography. Despite hazards associated with the explosiveness of its salts, the acid is often preferred in certain syntheses. Other acids of noncoordinating anions, such as fluoroboric acid and hexafluorophosphoric acid are susceptible to hydrolysis, whereas perchloric acid is not. It provides strong acidity with minimal interference because perchlorate is weakly nucleophilic (explaining the high acidity of HClO 4). The most recent estimate of its aqueous p K a is −15.2 ☒.0. That its p K a is lower than −9 is evidenced by the fact that its monohydrate contains discrete hydronium ions and can be isolated as a stable, crystalline solid, formulated as. ![]() Perchloric acid, a superacid, is one of the strongest Brønsted–Lowry acids. Additionally it is a useful component in etching of chrome. Perchloric acid is one of the most proven materials for etching of liquid crystal displays and critical electronics applications as well as ore extraction and has unique properties in analytical chemistry. Several million kilograms are produced annually. The growth in rocketry has led to increased production of perchloric acid. Perchloric acid is mainly produced as a precursor to ammonium perchlorate, which is used in rocket fuel. Thus, if left open to the air, concentrated perchloric acid dilutes itself by absorbing water from the air.ĭehydration of perchloric acid gives the anhydride dichlorine heptoxide: 2 HClO 4 + P 4O 10 → Cl 2O 7 + H 2P 4O 11 Uses This form of the acid is stable indefinitely and is commercially available. Perchloric acid forms an azeotrope with water, consisting of about 72.5% perchloric acid. These solids consist of the perchlorate anion linked via hydrogen bonds to H 2O and H 3O + centers. ![]() It forms at least five hydrates, several of which have been characterized crystallographically. The reaction gives nitrous oxide and perchloric acid due to a concurrent reaction involving the ammonium ion and can be concentrated and purified significantly by boiling off the remaining nitric and hydrochloric acids.Īnhydrous perchloric acid is an unstable oily liquid at room temperature. It can also be made by mixing nitric acid with ammonium perchlorate and boiling while adding hydrochloric acid. Treatment of barium perchlorate with sulfuric acid precipitates barium sulfate, leaving perchloric acid. The alternative route, which is more direct and avoids salts, entails anodic oxidation of aqueous chlorine at a platinum electrode. ![]() The concentrated acid can be purified by distillation. Treatment of such solutions with hydrochloric acid gives perchloric acid, precipitating solid sodium chloride: The traditional method exploits the high aqueous solubility of sodium perchlorate (209 g/100 mL of water at room temperature). Perchloric acid is produced industrially by two routes.
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