CHLORINE. 235 



chloric acid or chlorides. The others are more corroborative than 

 decisive. 



Nitro-hydrochloric acid, Acidum nitro-hydrochloricum, Aqua 

 regla (Nitro-muriatic acid). Obtained by mixing 18 c.c. of nitric 

 acid with 82 c.c. of hydrochloric acid. The two acids act chemically 

 upon each other, forming chloronitrous gas, chlorine, and water : 



HN0 3 + 3HC1 = NOC1 + 2H 2 O + 2C1. 



The dissolving power of this acid upon gold and platinum depends 

 on the action of the free chlorine. The action on platinum is repre- 

 sented by this equation : 



2HNO 3 + 8HC1 + Pt = H 2 Pt.Cl 6 f 2NOC1 -f 4H 2 O. 



Chloroplatinic acid, H 2 PtCl 6 , is in solution. This is used as a test- 

 solution. 



The official diluted nitrohydrochloric acid is made by mixing 182 c.c. of hydro- 

 chloric acid with 40 c.c. of nitric acid and adding, when effervescence has 

 ceased, 782 c.c. of water. 



Compounds of chlorine -with oxygen. There is no method known 

 by which to combine chlorine and oxygen directly, all the compounds formed 

 by the union of these ele%ients being obtained by indirect processes. The 

 oxides of chlorine are the following: 



Chlorine monoxide or hypochlorous oxide, C1 2 O. 

 Chlorine dioxide, C1Q 2 . 



Chlorine heptoxide, C1 2 O 7 . 



The first two oxides are yellow or brownish-yellow gases ; the third one is a 

 colorless liquid ; all combine with water, forming hypochlorous, chlorous and 

 chloric, and perchloric acid, thus : 



C1 2 O + H 2 O = 2HC1O. 



2C10 2 + H 2 HC10 2 + HC10 3 . 



C1 2 O 7 + H 2 O 2HC10 4 . 



The oxide, C1 2 O 5 , from which chloric acid, HC1O 3 , might be formed, is not 

 known. The chlorine oxides, the acids, and many of their salts are distin- 

 guished by the great facility with which they decompose, frequently with vio- 

 lent explosion, for which reason care must be taken in the preparation and 

 handling of these compounds. 



Chlorine acids. 



Hypochlorous acid, HC1O. Chloric acid, HC1O 8 . 



Chlorous acid, HC1O 2 . Perchloric acid, HC1O 4 . 



Hydrochloric acid, HC1. 



