Nomenclature
CAS number: 7631-90-5
Sodium acid sulfite.
HNaO
3S; mol wt 104.06.
H 0.97%, Na 22.09%, O 46.13%, S 30.81%.
NaHSO
3.
Description and references
The bisulfite of commerce consists chiefly
of sodium metabisulfite, Na2S2O5,
and for all practical purposes possesses the same properties as the
true bisulfite. Toxicity: Hoppe, Goble, J. Pharmacol. Exp. Ther. 101, 101 (1951).
Properties
White, crystalline powder; SO2 odor;
disagreeable taste; on exposure to air it loses some SO2 and is gradually oxidized to sulfate. d 1.48. Sol in 3.5 parts cold water, 2 parts
boiling water, in about 70 parts alcohol. Its aq soln is acid. Keep well closed and in a cool place. LD50 i.v. in rats:
115 mg/kg (Hoppe,
Goble).Caution
Potential symptoms of overexposure
are irritation of eyes, skin, mucous membranes. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH
97-140, 1997) p 282.Use
As disinfectant and bleach, particularly for wool;
in dyeing for preparing hot and cold indigo vats; in paper-making
in place of sodium hyposulfite to remove Cl from bleached fibers;
as stripper (reducer) in laundering; to remove permanganate stains
from skin and clothing; to render certain dyes sol; manuf sodium hydrosulfite;
coagulating rubber latex; as preservative for deteriorative liqs or
solns used for technical purposes; as antiseptic in fermentation industries.
As preservative and bleach in food. Pharmaceutic aid (antioxidant).