232 NON-METALS AND THEIR COMBINATIONS. 



heat that light is produced, or, in other words, combustion takes place. 

 Thus, hydrogen, phosphorus, and many metals burn easily in chlorine. 

 The affinity between chlorine and hydrogen is intense, a mixture of 

 the two gases being highly explosive. Such a mixture, kept in the 

 dark, will not undergo chemical change, but when ignited, or when 

 exposed to direct sunlight, combination between the two elements 

 occurs instantly with an explosion. The affinity of chlorine for 

 hydrogen is also demonstrated by its property of decomposing water, 

 ammonia, and many hydrocarbons (compounds of carbon with hydro- 

 gen), such as oil of turpentine, C 10 H 16 , and others : 



H 2 + 2C1 = 2HC1 -f O. 



NH 3 + 3C1 = 3HC1 + N. 



C 10 H 16 + 16C1 = 16HC1 + IOC. 



As shown by these formulas, hydrochloric acid is formed, while 

 the other elements are set free. 



Chlorine is a strong disinfecting, deodorizing, and bleaching agent ; 

 it acts as such either directly by combining with certain elements of 

 the coloring or odoriferous matter, or, indirectly, by decomposing 

 water with liberation of oxygen, which in the nascent state that is, 

 at the moment of liberation has a strong tendency to oxidize other 

 substances. 



It should be noted that perfectly dry chlorine has practically no action on 

 other substances when also dried. In the absence of all moisture it has no 

 bleaching action. This inactivity of dry chlorine is exemplified by the fact that 

 it is now sold in steel cylinders. As ordinarily used, however, it acts readily, 

 because of the moisture in the atmosphere, and on objects, even if water is not 

 supplied directly. 



Compound solution of chlorine, Liquor chlori compositus (Chlorine 

 water). Cold water absorbs about two volumes of chlorine, which is equal to 

 0.4 per cent, by weight. This solution is unstable because the chlorine grad- 

 ually combines with hydrogen of water, while oxygen is set free. It is for this 

 reason that the U. S. P. has substituted for ordinary chlorine water the com- 

 pound solution of chlorine, which is to be freshly made when wanted. It is 

 prepared by digesting in a large flask potassium chlorate with hydrochloric 

 acid and then adding water to dissolve the liberated chlorine, as also some 

 chlorinated products and the potassium chloride which are formed. The 

 reaction, when complete, is this : 



KC10 3 + 6HC1 == KC1 + 3H 2 O + 6C1. 

 Chlorine water is a greenish-yellow liquid, having the odor of chlorine. 



Hydrochloric acid, Acidum hydrochloricum, ifCl = 36.18 

 (Muriatic acid). This acid occurs in the gastric juice of mammalia, 



