102 NON-METALS AND THEIR COMBINATIONS. 



liquid, having the odor and taste of chlorine. It must be kept 

 in the dark, as otherwise decomposition takes place. 



Hydrochloric acid, Acidum hydrochloricum, HC1 = 36.4 (Chlor- 

 hydric acid, Muriatic acid, Hydrogen chloride). One volume of 

 hydrogen combines with one volume of chlorine to form two 

 volumes of hydrochloric acid. 



Another method for obtaining it is the decomposition of 

 chlorides by sulphuric acid : 



NaCl + H 2 S0 4 = HC1 + NaHSO 4 ; 

 Or 



2NaCl + H 3 SO 4 = 2HC1 + Na 2 SO 4 . 



Thus obtained, hydrochloric acid is a colorless gas, having a 

 sharp, penetrating odor, and is very irritating when inhaled. 

 It is not combustible, not a supporter of combustion, and has 

 great affinity for water, which property is the cause of the 

 formation of white clouds whenever the gas comes in contact 

 with the vapors of water, or with moist air; the white clouds 

 being formed of minute particles of the liquid hydrochloric 

 acid. 



Whilst hydrochloric acid is a gas, this name is also used for 

 its solution in water, one volume of which at ordinary tempera- 

 ture takes up over 400 volumes of the gas. 



The hydrochloric acid of the U. 8. P. is the acid containing 

 31.9 per cent, of HC1. It is a colorless, fuming liquid, having 

 the odor of the gas, strong acid properties, and a specific gravity 

 of 1.16. The officinal diluted hydrochloric acid is made by 

 mixing 6 parts of the above acid with 13 parts of water. 



The same antidotes may be used as for nitric acid. 



Tests for hydrochloric acid and chlorides. 



1. To hydrochloric acid, or to solution of chlorides, add silver 

 nitrate; a white, curdy precipitate is produced, which is soluble 

 in ammonium hydrate, but insoluble in nitric acid : 



AgN0 3 + Nad = NaXOg + AgCl ; 

 AgNO s + HC1 = H]SO 3 + AgCl. 



2. Add solution of mercurous salt (mercurous nitrate) : a 



