Acids & Salts Available — Bulk Only

Sodium Bisulfite (Sodium Hydrogen Sulfite)

NaHSO3
CAS 7631-90-5 · Formula HNaO3S · MW 104.06 g/mol

A sulfur-based reducer that scavenges oxygen, strips chlorine, and bleaches across water, pulp, and textile streams. It is used as a reducing and oxygen-scavenging agent, a bleaching agent for wood pulp and textiles, an antioxidant and preservative, a dechlorinating agent in water treatment, and a processing aid in dyeing and tanning.

Safety Data Sheet
UN Number
UN 2693
Hazard Class
Class 8
HS Code
2832.10
At a Glance
Material Family
Acids & Salts
Record Type
Pure compound
Primary Role
Preservation
Functional Roles
SODIUM BISULFITE
ANTIOXIDANTHAIR WAVING OR STRAIGHTENINGPRESERVATIVEREDUCING
Applications & Use Cases
  • Reducing and scavenging: Oxygen scavenger and reducing agent for water and boiler systems.
  • Bleaching: Bleaching agent for wood pulp, wool, and textiles.
  • Dechlorination: Removes residual chlorine in water and effluent treatment.
  • Antioxidant and preservative: Antioxidant and preservative in industrial and food-grade uses.
Physical Properties
Melting Point
Decomposes
Boiling Point
Decomposes
Density
1.48 at 20 °C
Solubility
29 %
Vapor Pressure
Vapor pressure, kPa at 20 °C: 2.4
pH
2,5-5,5 (10 % aqueous solution)
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

DOT / UN Transport Classification
DOT hazard class 8 placard
UN / DOT NumberUN 2693
Hazard Class / DivisionClass 8
Proper Shipping NameBisulfites, aqueous solutions, n.o.s.

Transport classification per the UN Model Regulations / 49 CFR 172.101 Hazardous Materials Table. Confirm against the grade-specific SDS (Section 14) before shipping.

HS / Tariff Classification
Harmonized System (HS) Code — 6-digit international heading
2832 . 10
Chapter 28
Inorganic chemicals; compounds of precious metals and rare-earth metals
Heading 28.32
Internationally harmonized (WCO HS)
Subheading 2832.10
6-digit international code — national tariff line adds further digits
Chemical Identity
CAS Number
7631-90-5
Molecular Formula
HNaO3S
Molecular Weight
104.06 g/mol
IUPAC Name
sodium hydrogen sulfite
INCI Name
SODIUM BISULFITE
PubChem CID
InChI Key
DWAQJAXMDSEUJJ-UHFFFAOYSA-M
Synonyms & Trade Names
SODIUM BISULFITE Sodium hydrogen sulfite sodium hydrogensulfite Sodium bisulphite Monosodium sulfite Sulfurous acid, monosodium salt Sodium sulhydrate Uantax SBS Hydrogen sodium sulfite Hydrogen sulfite sodium Monosodic sulphite Sodium hydrosulfite(DOT) Bisulfite de sodium Sodium bisulfite (1:1) Sodium sulfite (NaHSO3) Sodium bisulfite (NaHSO3) Fr-62 Sulfurous acid, sodium salt (1:1) INS NO.222
Full Description

Sodium bisulfite (CAS 7631-90-5), NaHSO3, is a reducing-agent salt commonly supplied in solution. It is used as a reducing and oxygen-scavenging agent, a bleaching agent for wood pulp and textiles, an antioxidant and preservative, a dechlorinating agent in water treatment, and a processing aid in dyeing and tanning.

Frequently Asked Questions

What is sodium bisulfite used for?

Sodium bisulfite (CAS 7631-90-5, NaHSO3), commonly supplied in solution, is used as a reducing and oxygen-scavenging agent for water and boiler systems, a bleaching agent for wood pulp and textiles, a dechlorinating agent that removes residual chlorine in water and effluent treatment, and an antioxidant and preservative.

Is baking soda the same as sodium bisulfite?

No. Baking soda is sodium bicarbonate (NaHCO3), an alkali. Sodium bisulfite is NaHSO3 (CAS 7631-90-5), an acidic reducing-agent salt. Note also that sodium bisulfite differs from sodium bisulfate (NaHSO4); the three are distinct chemicals.

What is the pH of sodium bisulfite?

Sodium bisulfite solutions are acidic, consistent with its role as a reducing and dechlorinating agent. Exact solution pH varies with concentration and is documented on the SDS.

How is sodium bisulfite shipped and what is the UN number?

Sodium bisulfite is assigned UN 3260 and ships under DOT/IMDG hazmat rules with appropriate packaging and documentation. It classifies under HS 2832.10 (sodium sulfites). Our team coordinates compliant shipping for each order.

How is sodium bisulfite supplied and priced in bulk?

We supply sodium bisulfite, commonly as solution, in industrial quantities with CoA and SDS per lot. Bulk pricing depends on concentration, packaging, and volume; request a bulk quote for current pricing and lead time.

Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.