Home Categories Inorganic chemistry Sulfur dioxide solution
A7322112

Sulfur dioxide solution , AR,SO2≥6% , 7782-99-2

Synonym(s):
Sulfurous acid;Sulfurous anhydride

CAS NO.:7782-99-2

Empirical Formula: H2O3S

Molecular Weight: 82.08

MDL number: MFCD00011335

EINECS: 231-973-1

Update time: 2022-07-08

PRODUCT Properties

Density  1.03 g/mL at 25 °C(lit.)
vapor density  2.3 (vs air)
solubility  solution of SO2 in H2O
pka 1.92(at 25℃)
form  Liquid
color  Colorless
PH pKa1= 1.658, pKa2 = 6.820(25℃)
Water Solubility  Miscible with water.
Sensitive  Air Sensitive
Merck  14,8976
Dielectric constant 15.6(0℃)
Stability: Stable. Incompatible with strong bases.
InChIKey LSNNMFCWUKXFEE-UHFFFAOYSA-N
LogP -1.579 (est)

Description and Uses

Sulfurous Acid is a weak and unstable inorganic acid, which is considered an aqueous solution of sulfur dioxide in water. It is formed theoretically by burning sulfur to produce sulfur dioxide, which is then reacted with water. However, there is no evidence that sulfurous acid exists in solution, while the molecules of which has been detected in the gas phase, since the reaction is reversible and the acid readily decomposes back into the reactants. Sulfurous acid is not usually available in its acid form, but more commonly prepared as its sodium or potassium salts.
Sulfurous acid and its salts are commonly applied as powerful reducing agents and disinfectant agents due to its strong reducibility. It is also considered as a mild bleaching agent especially for applications having chlorine sensitive materials. Besides, Sulfurous acid is a food additive listed on the EAFUS food Additive Database (Jan. 2001).

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.”

Safety

Symbol(GHS) 
GHS05,GHS07
Signal word  Danger
Hazard statements  H314-H332
Precautionary statements  P261-P271-P280-P303+P361+P353-P304+P340+P310-P305+P351+P338
Hazard Codes  C,Xn
Risk Statements  20-34-36/38
Safety Statements  26-36/37/39-45
RIDADR  UN 1833 8/PG 2
WGK Germany  1
RTECS  WT2775000
10-23
TSCA  Yes
HazardClass  8
PackingGroup  II
HS Code  28111990

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