Editing Perchloric acid (section)

==Production==
Perchloric acid is produced industrially by two routes. The traditional method exploits the high aqueous solubility of [[sodium perchlorate]] (209 g/100 ml of water at room temperature). Treatment of such solutions with [[hydrochloric acid]] gives perchloric acid, precipitating solid sodium chloride:
:NaClO<sub>4</sub> + HCl → NaCl + HClO<sub>4</sub>
The concentrated acid can be purified by [[distillation]]. The alternative route, which is more direct and avoids salts, entails [[anodic oxidation]] of aqueous chlorine at a platinum electrode.<ref name=Ullmann>Helmut Vogt, Jan Balej, John E. Bennett, Peter Wintzer, Saeed Akbar Sheikh, Patrizio Gallone "Chlorine Oxides and Chlorine Oxygen Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a06_483}}.</ref><ref>{{Cite journal |doi= 10.1002/cite.330350203 |title= Herstellung von Perchlorsäure durch anodische Oxydation von Chlor |journal= Chemie Ingenieur Technik |volume= 35 |issue= 2 |pages= 78 |year= 1963 |last1= Müler |first1= W. |last2= Jönck |first2= P.}}; [https://depatisnet.dpma.de/DepatisNet/depatisnet?action=bibdat&docid=DE000001031288B German patent DE1031288B]; [https://patents.google.com/patent/US2846383 US patent US2846383A].</ref>

===Laboratory preparations===
It can be distilled from a solution of potassium perchlorate in sulfuric acid.<ref>{{cite book|first=M.|last=Schmeisser|chapter=Perchloric Acid|title=Handbook of Preparative Inorganic Chemistry|edition=2nd|editor-first=G.|editor-last=Brauer|publisher=[[Academic Press]]|year=1963|place=NY,NY|volume=2|page=318 }}</ref> Treatment of [[barium perchlorate]] with [[sulfuric acid]] precipitates [[barium sulfate]], leaving perchloric acid. It can also be made by mixing [[nitric acid]] with [[ammonium perchlorate]] and boiling while adding hydrochloric acid. 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.