WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
28.06 - Hydrogen chloride (hydrochloric acid); chlorosulphuric acid. 2806.10 2806.20 - Hydrogen chloride (hydrochloric acid) - Chlorosulphuric acid (A) HYDROGEN CHLORIDE (HYDROCHLORIC ACID) Hydrogen chloride (HCI) is a colou~lessfuming gas with a suffocating odour, obtained by the action of hydrogen (or of water and coke) on chlorine, or by the action of sulphuric acid on sodium chloride. It is easily liquefied under pressure and very soluble in water. It is presented under ressure in liquid form in steel cylinders. It is also presented in concentrated aqueous solutions &ually 28 to 38 %) (hydrochloric acid, muriatic acid, spirits of salt) in glass or earthenware containers or in rubber-lined tank wagons or tank trucks. These pungent-smelling solutions are yellowish if the product contains impurities (ferric chloride, arsenic, sul hur dioxide, sulphuric acid), and colourless if pure. The concentrated solutions give off white mes in damp air. % Hydrochloric acid has many uses, e.g., pickling iron, zinc or other metals, extractin gelatin from bones, purifying animal black, preparing metal chlorides, etc. Hydrogen chlori e gas is often employed in or anic s theses (e.g., in the manufacture of chloroprene, vinyl chloride, artificial camphor, rub er hy ochloride). f % 'I? (B) CHLOROSULPHURIC ACID (CHLOROSULPHONICACID) b Chlorosul huric acid, commercially designated as chlorosulphonic acid "sulphuric chlorohy in ") and havin the chemical formula C1SO20H,resuIts fiom the dry corn ination of hydrogen chloride with s phur trioxide or oleum. It is a highly corrosive, colourless or brownish liquid with an irritating odour; it fumes in a humid atmosphere and decomposes on contact with water or if heated. It is used in organic syntheses (manufacture of saccharin, thioindigo, indigosols, etc.). The heading excludes hypochlorous, chloric or perchloric acids heading 28.11). The heading also excludes sulphur dichlonde dioxide (sulphuryl chloride) (hea ing 28.12), which is sometimes erroneously referred to as "chlorosulphuric acid".
1.- Except where the context otherwise requires, the headings of this Chapter apply only to : (a) Separate chemical elements and separate chemically defined compounds, whether or not containing impurities; (b) The products mentioned in (a) above dissolved in water; (c) The products mentioned in (a) above dissolved in other solvents provided that the solution constitutes a normal and necessary method of putting up these products adopted solely for reasons of safety or for transport and that the solvent does not render the product particularly suitable for specific use rather than for general use; (d) The products mentioned in (a), (b) or (c) above with an added stabiliser (including an anti-caking agent) necessary for their preservation or transport; (e) The products mentioned in (a), (b), (c) or (d) above with an added anti-dusting agent or a colouring substance added to facilitate their identification or for safety reasons, provided that the additions do not render the product particularly suitable for specific use rather than for general use.