Nitrosylsulfuric Acid (HNSO5)
Nitrosylsulfuric acid (HNSO5), also known as chamber acid, is a chemically defined inorganic compound with the formula HNO2SO4 or [NO]+[HSO4]-. It is a sulfonitric acid, which is expressly included in tariff item 2808.00.00. The product is not an organic compound, so it falls within Chapter 28, and its chemical definition is clear under the chapter notes.
Import Duty Rates by Country of Origin
| Origin Country | MFN Tariff | Surtaxes | Total Effective Rate |
|---|---|---|---|
| 🇨🇳China | Free | — | Free |
| 🇲🇽Mexico | Free | — | Free |
| 🇺🇸United States | Free | — | Free |
| 🇩🇪Germany | Free | — | Free |
| 🇯🇵Japan | Free | — | Free |
PGA flags (2)Show detailsHide detailsCFIAAll ProgramsRequiredHCActive Pharmaceutical IngredientsMay be required
- CFIA
All Programs · Required
CANADIAN FOOD INSPECTION AGENCY: CFIA All Programs requires review / declaration data. CBSA's Single Window matching criteria match this classification number (Within Range 2807000000–2808000000).
- HC
Active Pharmaceutical Ingredients · May be required
May require HC Active Pharmaceutical Ingredients depending on intended use (HC13) and Canadian product category (HC01). Matching criteria: Equal To 2808000000. Logic: MATCH IF (Valid HS Code) AND (Intended Use Code) AND (Valid Canadian Product Category).
CBSA Single Window matching criteria, unknown
More Specific Codes
This product may fall under a more specific subheading:
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If the product is misidentified and is actually sulfuric acid
Sulfuric acid is classified under heading 28.07, not as a sulfonitric acid.
If the product is a different inorganic acid or a complex acid not covered by heading 28.08
Other inorganic acids are classified under heading 28.11 when not specifically named.
Not sure which classification is right?
The Tariff Assistant works through the GRI rules on your specific product to reach the right tariff item — and can price the duty on it in the same conversation.
Import Tips & Compliance
• Provide the chemical formula and a certificate of analysis to confirm the product is nitrosylsulfuric acid, not a mixture of nitric and sulfuric acids
• Check if the product is subject to import controls under the Chemical Weapons Convention; if so, a permit from Global Affairs Canada may be required
• Ensure the product is properly packaged and labelled as a corrosive substance to comply with CBSA and transport regulations
Related Products under Tariff item 2808.00.00
Azeotropic Nitric Acid 68.5%
Azeotropic nitric acid at 68.5% concentration, a constant-boiling mixture used as a laboratory standard. It is a separate chemically defined compound (HNO3) in aqueous solution, meeting the requirements of Chapter 28 Note 1.
Chamber Process Sulfonitric Acid
Chamber process sulfonitric acid is a product of the lead chamber process for sulfuric acid manufacture, consisting mainly of nitrosylsulfuric acid. It is a sulfonitric acid, which is expressly included in the wording of tariff item 2808.00.00. The product is an inorganic compound of nitrogen and sulfur, not an organic derivative, so it remains within Chapter 28.
Concentrated Nitric Acid 68%
High-purity nitric acid with 68% concentration, chemically defined as HNO3, used in industrial nitration and metal etching. It is a simple inorganic acid, classified under this tariff item.
Dilute Nitric Acid 10% Solution
A 10% aqueous solution of nitric acid, used for pH adjustment and cleaning. As a dilute solution of a chemically defined compound in water, it falls under Chapter 28 Note 1(b) and is classified in this tariff item.
Electropolishing Nitric Acid 50%
A 50% nitric acid solution formulated for electropolishing stainless steel. The acid base is chemically defined and the solution is simply an aqueous dilution, so it remains within the scope of Chapter 28.
Fuming Nitric Acid 98%
Fuming nitric acid at 98% concentration, containing dissolved nitrogen oxides. It is a form of nitric acid that meets the definition of a separate chemically defined compound, with the dissolved gases considered impurities or stabilizers.