Title: Perchloric Acid
CAS Registry Number: 7601-90-3
Molecular Formula: ClHO4
Molecular Weight: 100.46
Percent Composition: Cl 35.29%, H 1.00%, O 63.70%
Line Formula: HClO4
Literature References: Prepd from potassium perchlorate and sulfuric acid: Schmeisser in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 318-320. Comprehensive monograph: J. C. Schumacher, Perchlorates (Reinhold, New York, 1960).
Properties: The anhydr acid is a colorless, volatile, very hygroscopic liquid. d22 1.768; bp11 19°. Dec when distilled at atmospheric pressure, sometimes with explosive violence. mp -112°. Combines vigorously with water with evolution of heat. Undergoes spontaneous and explosive decompn, hence it is marketed only in mixture with water contg 60-70% HClO4, density 1.5 and 1.6, respectively. The aq acid is very caustic and may deflagrate in contact with oxidizable substances. Density of aq solns at 15°: 1% = 1.0050; 10% = 1.0597; 20% = 1.1279; 30% = 1.2067; 40% = 1.2991; 50% = 1.4103; 60% = 1.5389; 70% = 1.6736. Density of aq solns at 25°: 65.0% = 1.597; 70.0% = 1.664; 75.0% = 1.731.
Melting point: mp -112°
Boiling point: bp11 19°
Density: d22 1.768; Density of aq solns at 15°: 1% = 1.0050; 10% = 1.0597; 20% = 1.1279; 30% = 1.2067; 40% = 1.2991; 50% = 1.4103; 60% = 1.5389; 70% = 1.6736.
CAUTION: Corrosive to skin, mucous membranes.
Use: The acid in analytical chemistry as an oxidizer and for separation of potassium from sodium. Its salts for explosives and for plating of metals. |