Decomposition of Oxides and Salts by Chlorine. 227 



rine. It was then agitated with a repeatedly renewed quantity 

 of atmospheric air until no free chlorine could be perceived 

 in it. This solution had the peculiar astringent taste of hypo- 

 chlorous acid, and its powerful bleaching properties. It was 

 oversaturated with ammonia and heated to the boiling-point, 

 and having added an excess of nitric acid, it was preci- 

 pitated by nitrate of silver. After separating it from this 

 precipitate, the barytes was thrown down by sulphuric acid. 

 Three determinations, conducted in this manner, gave the fol- 

 lowing results. For each determination a fresh liquid was 

 prepared. 



I. 0*550 chloride of silver =0* 136 chlorine. 

 0*243 sulphate of barytes = 0*1 59 barytes. 



This gives 818 chlorine to 957 barytes. 

 II. 1*4-68 chloride of silver =0*361 chlorine. 

 0*654 sulphate of barytes = 0*429 barytes. 



This gives 805 chlorine to 957 barytes. 



III. 1*836 chloride of silver =0*453 chlorine. 

 0*781 sulphate of barytes = 0*5 13 barytes. 



This gives 843 chlorine to 957 barytes. 



The average of these three gives 822 chlorine to 957 bary- 

 tes, or nearly 2 equivalents. 



The question which now naturally presents itself is, in what 

 manner can the chlorine be contained in this liquid, and in 

 what combinations? The following experiments were in- 

 stituted in order to ascertain this : — 



To part of the original liquid a solution of nitrate of silver 

 was added, by which a pure isohite precipitate of chloride of 

 silver was formed, which increased by standing. Another por- 

 tion was treated with barytes water until the smell and bleach- 

 ing reaction of hypochlorous acid had disappeared. Nitrate 

 of silver now formed a black precipitate, which gradually de- 

 composed, giving off oxygen. 



The cause of this striking difference in the two reactions is 

 evidently that in the first instance all the base was combined 

 with chlorine in the form of chloride, while hypochlorous 

 acid remaining free in the liquid, gradually increased the pre- 

 cipitate by its own decomposition. In the second case, the 

 hypochlorous acid being combined with barytes gave the black 

 precipitate, consisting of a mixture of chloride with peroxide 

 of silver. 



To test the correctness of this explanation the following ex- 

 periments were made: — 



Aqueous hypochlorous acid was neutralized with barytes. 

 This salt possessed no bleaching properties. Carbonic acid 

 precipitated carbonate of barytes. The liquid, after separa- 



