S

Sulfurous acid

IUPAC: sulfurous acid

H2SO3 Acids CAS 7782-99-2
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Quick Reference
Formula / NotationH2SO3
CAS Number7782-99-2
Molecular Weight82.08
Solubility558.5 mg/mL
AppearanceSulfurous acid appears as a colorless liquid with a pungent burning sulfur odor. Corrosive to metals and tissue.
Also Known As7782-99-2; Sulphurous acid; Schweflige saure; H2SO3; EINECS 231-973-1; acide sulfureux; acido sulfuroso; schweflige Saeure; trioxosulfuric acid; dihydroxidooxidosulfur
CategoryAcids

What is Sulfurous acid?

Sulfurous acid is a sulfur oxoacid. It is a conjugate acid of a hydrogensulfite. It is a tautomer of a sulfonic acid.

Formula & Notation

H2SO3

IUPAC Name: sulfurous acid

Other Names / Synonyms: 7782-99-2; Sulphurous acid; Schweflige saure; H2SO3; EINECS 231-973-1; acide sulfureux; acido sulfuroso; schweflige Saeure; trioxosulfuric acid; dihydroxidooxidosulfur

Properties & Characteristics

Appearance: Sulfurous acid appears as a colorless liquid with a pungent burning sulfur odor. Corrosive to metals and tissue.. Molecular formula: H2O3S. Molecular weight: 82.08 g/mol. Solubility: 558.5 mg/mL. LogP: -0.5.

Physical Data

PropertyValue
Molecular Weight82.08
Solubility558.5 mg/mL
AppearanceSulfurous acid appears as a colorless liquid with a pungent burning sulfur odor. Corrosive to metals and tissue.

Uses & Applications

Used in industrial chemical synthesis, fertilizer production, battery electrolytes, metal processing, and laboratory acid-base reactions.

Safety Information

Corrosive. Causes severe burns to skin, eyes, and respiratory tract. Wear appropriate PPE including gloves, goggles, and lab coat. Consult SDS before use.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Sulfurous acid
Formula H2SO3
CAS Number 7782-99-2
Molecular Weight 82.08
Category Acids
Synonyms 7782-99-2; Sulphurous acid; Schweflige saure; H2SO3; EINECS 231-973-1; acide sulfureux; acido sulfuroso; schweflige Saeure; trioxosulfuric acid; dihydroxidooxidosulfur

Frequently Asked Questions

Sulfurous acid is a sulfur oxoacid. It is a conjugate acid of a hydrogensulfite. It is a tautomer of a sulfonic acid.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.