Nitrosylsulfuric Acid (Chamber Acid)
Nitrosylsulfuric acid (HNO2SO4), also known as chamber acid, is used in sulfuric acid production and nitrating mixtures. Classified under HTS 2811.19.61.90 as an other inorganic acid, it is a complex oxygen compound of nonmetals (sulfur and nitrogen). Meets Chapter 28 definition for chemically defined inorganic acids.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If primarily sulfuric acid with minor nitrosyl content
Predominantly H2SO4 compositions fall under 2807 as sulfuric acid, per principal function.
If considered a complex salt of inorganic base
Chapter note specifies double salts in 2842; if interpreted as metal salt derivative, reclassifies there.
If for impure or stabilized preparations
Commercial grades with organic stabilizers become 'other chemical preparations' in 3824 per Chapter exclusions.
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Import Tips & Compliance
• Provide detailed chemical composition and CAS number (7782-78-7) in entry docs to distinguish from sulfuric acid in 2807
• Classify as UN 2305 corrosive; use IBC totes with proper placarding to avoid delays
Related Products under HTS 2811.19.61.90
Hypophosphorous Acid 50% Solution
Hypophosphorous acid (H3PO2) 50% aqueous solution serves as a reducing agent in chemical synthesis and electroless plating. It is classified in HTS 2811.19.61.90 as an other inorganic phosphorus oxyacid. Excluded from Chapter 28 note 2 only for specific carbon compounds, qualifying as chemically defined.
Boric Acid Powder Technical Grade
Technical grade boric acid (H3BO3) powder used in ceramics, herbicides, and antiseptics. Although subheading 2810.00 covers boric acid primarily, purer technical grades or specific forms may fall under 2811.19.61.90 as other inorganic oxygen compounds.
Germanium Dioxide Hydrated (Germanic Acid)
Hydrated germanium dioxide, or germanic acid (H2GeO3), used in fiber optics and catalysts. Falls under HTS 2811.19.61.90 as other inorganic germanium oxyacid.
Silicic Acid Precipitated
Precipitated silicic acid (H2SiO3 gel) used as anti-caking agent and absorbent. Classifies in HTS 2811.19.61.90 as other inorganic acid of nonmetal silicon. Distinct from silica in 2811.22.
Arsenic Acid Solution 70%
Arsenic acid (H3AsO4) 70% solution is used in wood preservatives and glass manufacturing. Classified in HTS 2811.19.61.90 as an other inorganic oxyacid of nonmetal arsenic. Qualifies under Chapter 28 for chemically defined inorganic acids.
Antimonic Acid Colloidal
Colloidal antimonic acid (HSbO3·nH2O) is applied in flame retardants and catalysts. It is an other inorganic acid under HTS 2811.19.61.90, oxygen compound of nonmetal antimony. Chemically defined despite colloidal form.