232 Decomposition of Oxides and Salts by Chlorine. 



Two basic pyrophosphates behaved in exactly the same 

 manner. 



The next salt I subjected to this treatment was sulphate of 

 soda. A solution of this perfectly neutral salt was saturated 

 at the common temperature with chlorine, which was freely 

 absorbed by it. The liquid remained colourless, which shows 

 that the chlorine absorbed was not contained, as such, in solu- 

 tion. This neutral sulphate of soda was indeed decomposed. 

 The liquid, after saturation with chlorine, consisted of a mix- 

 ture of bisulphate of soda with chloride of sodium and free 

 hypochlorous acid. Whether any neutral sulphate remained 

 undecomposed I have yet to ascertain. On being subjected 

 to distillation, hypochlorous acid passed over at the beginning 

 of the operation. The liquid which first distils contains most 

 of the acid. Each successive portion contains less of it than 

 the preceding. This compound possesses such powerful oxi- 

 dating properties, far exceeding, at the common temperature, 

 those of nitric acid, that it might doubtless become a valuable 

 aid to the chemist in many of his operattons. It might even 

 be made advantageously on a large scale in the above-de- 

 scribed manner; the same sulphate of soda would of course 

 serve for many operations. It is only necessary to boil down 

 the residue of distillation and heat it until all the chlorine is 

 driven out as hydrochloric acid, which also need not be lost. 

 It is now reconverted into neutral sulphate of soda, which 

 can be redissolved and treated with chlorine as before. 



The aqueous solution of hypochlorous acid may easily be 

 prepared so as to contain in a given weight more bleaching 

 power than the well-known lime compound. It will keep for 

 a considerable time, even when concentrated, with but very 

 little decomposition if protected from light, and, of course, 

 heat. I offer this as a hint for the consideration of manufac- 

 turers of bleaching powders. Should it prove a practical sim- 

 plification of the method hitherto used for preparing the 

 bleaching compounds, and thereby have any beneficial effect 

 on the manufactures for which these are required, I shall feel 

 myself amply rewarded. 



The salts of sulphuric acid with the following bases are de- 

 composed in like manner. Oxide of copper, peroxide of iron, 

 oxide of zinc, protoxide of manganese, also the double salt of 

 alumina and potash ; even sulphate of lead, when suspended 

 in water and treated in like manner, was slightly decomposed. 

 Chromate of potash was also decomposed. Borax was entirely 

 decomposed : the solution deposited after concentration cry- 

 stals of boracic acid. Nitrate of potash slightly. Acetate 

 of lead was decomposed, forming chloride and peroxide. 



