362 CHLORINE. 



the potassium family) often combine together, forming oxichlo- 

 rides, which are in general of slight solubility. 



Chlorine is also absorbed by alkaline solutions, and combina- 

 tions are formed which bleach and exhibit many of the proper- 

 ties of the free element. The state of the chlorine in these 

 compounds and also in dry chloride of lime, formed by exposing 

 hydrate of lime to chlorine gas, is still matter of uncertainty. 

 But they are not permanent compounds, and the chlorine even- 

 tually acts upon the metallic oxide, so as to produce a chloride, 

 a chlorate of the metal as will be afterwards explained. 



The following chlorides of the non-metallic elements will now 

 be particularly described : 



Hydrochloric acid. . . H Cl 

 Hypochlorus acid. . . Cl O 

 Peroxide of chlorine. . Cl O 4 



Hyperchloric acid. . Cl O 7 

 Chloride of nitrogen. . N C1 3 

 Perchloride of carbon. . C 4 C1 6 

 Protochloride of carbon. C 4 C1 4 



Subchloride of carbon. C 4 C1 2 

 Chlorocarbonic acid. . CO,C1 

 Chloride of boron. . B C1 3 

 Chloride of silicon. . Si C1 3 

 Chloride of sulphur. . S 2 Cl 

 Bichloride of sulphur. S C1 2 

 Terchl. of phosphorus. PC1 3 

 Perchl. of phosphorus. PC1 5 



HYDROCHLORIC ACID. 



Syn. CHLORHYDRIC ACID (Thenard), MURIATIC ACID. Eg. 

 455.13 or 36.47; C1H ; density 1269.5; 



This acid is one of the most frequently employed reagents in 

 chemical operations, and has long been known under the names 

 of spirit of salt, marine acid, and muriatic acid (from murias, sea- 

 salt). It was first obtained by Priestley in its pure form of a 

 gas, in 1772. 



Preparation. Hydrochloric acid is always obtained by the 

 action of oil of vitriol upon common salt. When the process 

 is conducted on a small scale and in a glass retort, equal weights 

 of common salt, oil of vitriol and water may be taken. The oil 

 of vitriol being mixed with l-3rd of the water in a thin flask, 

 and cooled, is poured upon the salt contained in a capacious 

 retort. A clean flask containing the remaining 2-3rds of the 

 water is then adapted to the retort as a condenser, as in the dis- 

 tillatory apparatus figured at page 59. Upon applying heat to 



