Nitroxylsulphonic acid

He said that hydroxynitrosylsulphonic acid is produced by the action of sulphur dioxide on nitrous acid in 70 per cent, sulphuric acid as a direct product of the interaction of nitrous and sulphurous acids, and not by the reduction of chamber crystals—nitroxylsulphonic acid—because he supposed that the latter cannot exist in less than 80 per cent, sulphuric acid. This assumption was shown, by W. C. Reynolds and W. H. Taylor, to be unfounded nitroxylsulphonic acid can exist in the presence of even 60 per cent, sulphuric acid. Further, the blue colour produced by the action of sulphurous acid, or other reducing agent, on a nitrite in the presence of a cone, sulphuric acid soln. of a copper salt, was supposed by F. Raschig to be the copper salt of P. Sabatier s acid, whereas, according to W. C. Reynolds and W. H. Taylor, the product is the complex which nitric acid forms with copper sulphate, and studied by W. Manchot, V. Kohlschiitter, etc.— vide supra. The existence of F. Raschig s nitrosylsulphonic acid may therefore be questioned, and the same remark applies to his statement of the identity of P. Sabatier s blue acid with the product of the reaction of nitrous and sulphurous acids in the presence of a copper salt. 

H. G. de Claubry found that when nitroxylsulphonic acid is heated with mercury, there is formed mercuric sulphate, sulphur dioxide, nitric oxide, and nitrogen and G. Lunge said that when a soln. in cone, sulphuric acid is shaken with mercury, nitric oxide and sulphuric acid are quantitatively formed and F. Rasehig observed that the reaction is completely inhibited by mercury, possibly with the formation of hydroxynitrosylsulphonic acid. A. Graire found that the acid is not reduced further than nitric oxide by agitation with mercury but if sulphur dioxide is present, some nitrous oxide may be formed. J. W. Dobereiner found that a soln. of nitroxylsulphonic acid in cone, sulphuric acid oxidizes mercury copper, silver, Zinc, and iron, and the liquid is coloured red, violet-blue, or purple and J. J. Berzelius added that nitric oxide is at the same time evolved. J. W. Dobereiner... 

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