Nomenclature
CAS number: 7664-39-3
Fluohydric acid.
HF; mol wt 20.01.
H 5.04%, F 94.94%.
Description and references
Soln of hydrogen fluoride gas in water. Obtained
by distilling calcium fluoride with H2SO4.
Vapor pressure data: Brosheer et al., Ind. Eng. Chem. 39, 423 (1947). Compn of
liq and vapor: Munter et al., ibid. 427. Review
of toxicology and human exposure: Toxicological
Profile for Fluorides, Hydrogen Fluoride, and Fluorine (PB2004-100002, 2003) 404 pp. See also Hydrogen Fluoride.
Properties
Colorless or almost colorless, fuming liquid.
Corrosive, poisonous. Miscible
with water. Weak acid: pKa 3.19. The 38.2% (w/w HF) soln is a binary azeotrope; bp 112.2°. Attacks glass
or stoneware, dissolving the silica. Keep
in plastic, lead, wax, or paraffin paper bottles. Has
been marketed in concns of about 47% and 53%. d 1.15-1.18.Caution
Potential symptoms of overexposure
are pulmonary edema, skin and eye burns, rhinitis, bronchitis, bone
changes. Direct contact may cause irritation of eyes, skin, nose
and throat. See NIOSH Pocket Guide
to Chemical Hazards (DHHS/NIOSH 97-140, 2003) p 168. See also Patty's Industrial Hygiene
and Toxicology vol. 2B, G. D. Clayton, F. E.
Clayton, Eds. (Wiley-Interscience, New York, 3rd ed., 1981) pp 2945-2948.Use
Cleaning cast iron, copper, brass; removing efflorescence
from brick and stone, or sand particles from metallic castings; working
over too heavily weighted silks; frosting, etching glass and enamel;
polishing crystal glass; decomposing cellulose; enameling and galvanizing
iron; increasing porosity of ceramics. Its salts are used as insecticides
and to arrest undesirable fermentation in brewing. Trace metal analysis.
Also used in analytical work to determine SiO
2, etc.