Nomenclature
CAS number: 7697-37-2
Aqua fortis; azotic acid; Salpeters"aure (German).
HNO
3; mol wt 63.01.
H 1.60%, N 22.23%, O 76.18%.
Description and references
Strong monobasic acid and oxidizing agent.
Usually produced by the catalytic oxidation of ammonia. Reviews
of industrial processes: F. D. Miles, Nitric
Acid, Manufacture and Uses (Oxford Univ. Press, 1961,
1963); W. Sommer in Ullmanns Encyklop"adie
der technischen Chemie vol. 15, pp 3-67 (3rd
ed., 1964). Pure acid prepd by distillation of concd nitric acid
with concd sulfuric acid; by treating sodium or potassium nitrate
with 100% H2SO4 and removing HNO3 by distillation; by fractional crystallization of concd HNO3. Review of preparation and properties of pure HNO3: S. A. Stern et al., Chem. Rev. 60, 185-207 (1960); S. S. Pannu, J. Chem. Educ. 61, 174-176 (1984). Reviews: Mellor's Vol. VIII, supplement II, Nitrogen (part 2), 278-352 (1967); Jones
in Comprehensive Inorganic Chemistry vol. 2, J. C. Bailar, Jr. et al., Eds. (Pergamon
Press, Oxford, 1973) pp 375-388; D. J. Newman in Kirk-Othmer Encyclopedia of Chemical Technology vol. 15 (Wiley-Interscience, New York, 1981) pp 853-871. Review
of photochemistry: J. R. Huber, Chem. Phys.
Chem. 5, 1663-1669 (2004).
Properties
Colorless liquid. Fumes in moist air. Characteristic
choking odor. d425 1.51. mp -41.59°. bp760 82.6°. Forms white, monoclinic crystals; d-41.6 (solid) 1.895. nD25 1.3920. Heat of fusion: 2.503 kcal/mole.
Heat of infinite dilution (298.1 K): -7971 cal/mole. Forms an azeotrope
with water, so-called constant boiling acid at 68% HNO3, bp 120.5°, d420 1.41. Develops yellow color in the presence of light due to nitrogen
oxide formation. Stains woolen fabrics and animal tissue a bright
yellow. Corrosive; oxidizer.
Reacts violently with combustible or readily oxidizable materials
such as alcohols, turpentine, charcoal, organic refuse. Reacts with
most metals to release hydrogen gas. Derivative
Nitric acid, concentrated.
Description and references
Defined as an aqueous solution containing
approx 70% HNO3.
Properties
Density of aq solns: d420 1.0036 (1% HNO3 w/w); 1.0543 (10%); 1.1150 (20%); 1.1800 (30%); 1.2463 (40%); 1.3100 (50%); 1.3667 (60%); 1.4134 (70%); 1.4521 (80%); 1.4826 (90%); 1.5129 (100%): International Critical Tables III, 58 (1928).Derivative
Nitric acid, fuming.
Description and references
Concentrated nitric acid containing dissolved
nitrogen dioxide. May be prepared from concd nitric acid by passing
nitrogen dioxide into it or by adding a small amount of organic reducing
agent, such as formaldehyde.
Properties
Yellow to brownish-red, clear, strongly fuming,
very corrosive liq; evolves suffocating, poisonous, yellowish-red
fumes of nitrogen dioxide and nitrogen tetroxide. The density increases
as the free NO2 content increases: concd HNO3 with 7.5% NO2 added d420 = 1.526; with 12.7% NO2 d420 = 1.544. Miscible with water. Corrosive;
oxidizer; poisonous.Caution
Potential symptoms of overexposure
are irritation of eyes, mucous membranes and skin; delayed pulmonary
edema, pneumonitis and bronchitis; dental erosion. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 224. See also Clinical Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins,
Baltimore, 5th ed., 1984) Section III, pp 8-11.Use
Manufacture of inorganic and organic nitrates and
nitro compounds for fertilizers, dye intermediates, explosives, rocket
fuels. As laboratory reagent, in photoengraving, metal etching.
Pharmaceutic aid (acidifier). Oxidizer. Solvent. Trace metal content
analysis.