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XXXII. On the Decomposition of Oxides and Salts hy Chlo- 

 rine, By Alexander W. Williamson, Esq.'^ 



'"T^HE compounds formed by the action of chlorine on the 

 J- hydrates of the alkalies and earths have long since at- 

 tracted the attention of chemists by their powerful bleaching 

 properties. As they were produced by simply bringing to- 

 gether chlorine with the base in presence of water, they were at 

 first considered as direct and simple combinations of chlorine 

 with the oxide, and were therefore called oxychlorides. 



Berzelius first showed this view to be untenable. He con- 

 sidered these compounds as containing a chloride and an oxy- 

 gen salt of chlorine, the acid of which he assumed identical 

 with that of Stadion, namely, 1 equivalent of chlorine to 3 of 

 oxygen. 



Serullas obtained by the evaporation of a solution of soda, 

 which had been treated with chlorine, crystals of chloride of 

 sodium, while the mother-liquid retained its bleaching proper- 

 ties unaltered. This experiment shows that a chloride and 

 an oxygen salt of chlorine, which possesses the bleaching pro- 

 perties, are contained in these compounds. 



By acting on the oxide of mercury with chlorine, Balard 

 succeeded in obtaining a combination of oxygen with chlorine, 

 which in its bleaching properties, as well as its salts, showed 

 much resemblance to the oxygen acid supposed to be con- 

 tained in the oxychlorides. He determined the composition 

 of this acid at 1 equivalent chlorine to 1 of oxygen. 



Millon has endeavoured to recall the ancient view with some 

 modification. He considers these compounds as analogous to 

 peroxides, so that the atoms of oxygen which the peroxide of a 

 metal contains beyond its oxide are here replaced by chlorine. 



This view was but imperfectly refuted, and indeed the sub- 

 ject remained in considerable doubt until Gay-Lussac made 

 known his interesting researches on the combinations of chlo- 

 rine with bases. 



I will here recall someof the principal facts, but must refer for 

 further particulars to the original treatise of this great master. 



If a mixture of a chloride with a corresponding salt of hy- 

 pochlorous acid in their equivalent parts be treated with sul- 

 phuric acid in excess, chlorine is given off. If, on the contrary, 

 the acid be added in a dilute state, and prevented by continual 

 agitation from acting unduly on any particular part, and only 

 so much acid be added as is sufficient to decompose the oxygen 

 salt, then hypochlorous acid is alone set free, and can be di- 



* Communicated by the Chemical Society ; having been read December 

 2, 1844. 



