Explanatory notes
… ‑ Other inorganic acids : 2811.11 ‑ ‑ Hydrogen fluoride (hydrofluoric acid) 2811.12 ‑ ‑ Hydrogen … S). A highly toxic, colourless gas with the foetid odour of rotten eggs. Presented under pressure in steel cylinders or … dioxide (SO 2 ). Obtained by combustion of sulphur, by roasting natural sulphides (particularly iron pyrites), or …