General Description
A colorless liquid with a pungent burning sulfur odor. Corrosive to metals and tissue.
Reactivity Profile
Colorless, corrosive, moderately toxic liquid. When heated to decomposition SULFUROUS ACID(7782-99-2) emits toxic fumes of oxides of sulfur [Lewis, 3rd ed., 1993, p. 1196].
Air & Water Reactions
Soluble in water with release of heat.
Health Hazard
TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Fire Hazard
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
Chemical Properties
colourless liquid
Chemical Properties
SULFUROUS ACID, colorless liquid, prepared by dissolving SO2 in H2O. Reagent grade H2SO3 contains approximately 6% SO2 in solution
Uses
As a bleaching agent, sulfurous acid is used for whitening wool, silk, feathers, sponge, straw, wood, and other natural products. In some areas, its use is permitted for bleaching and preserving dried fruits. The salts of sulfurous acid are sulfites.
Uses
Sulfurous acid (H2SO3) can be produced by burning sulfur to form sulfur dioxide (SO2) gas
and by then dissolving the gas in water to form sulfurous acid. This is the acid produced by
burning coal that has a high sulfur content; the gaseous sulfur dioxide by-product of combustion
then combines with atmospheric water to form “acid rain.”
Definition
A weak acid found only in
solution, made by passing sulfur(IV) oxide
into water. The solution is unstable and
smells of sulfur(IV) oxide. It is a reducing
agent, converting iron(III) ions to iron(II)
ions, chlorine to chloride ions, and orange dichromate(VI) ions to green chromium(III) ions.
Hazard
Toxic by ingestion and inhalation, strong
irritant to tissue.
Industrial uses
Sulfurous acid (H2SO3) is usually marketed as liquid SO2. The bulk of SO2 is produced
from off-smelter gases. Although handling of SO2 liquid requires special
equipment, it is frequently used as a pH regulator and depressant, primarily during
the treatment of complex sulfide ores. SO2 is largely used in North American operations
as a pyrite depressant and for the depression of galena during copper/lead
separation.
