CHLORINE. 119 



Properties. Chlorine is a yellowish-green gas, having a disagree- 

 able taste and an extremely penetrating, suffocating odor, acting 

 energetically upon the air-passages, producing violent coughing and 

 inflammation. It is about two and a half times heavier than air, 

 soluble in water, and convertible into a greenish-yellow liquid by a 

 pressure of about six atmospheres. 



Chemically, the properties of chlorine are well marked, and there 

 are but few elements which have as strong an affinity for other ele- 

 ments as chlorine ; it unites with all of them directly, except with 

 oxygen, nitrogen, and carbon, but even with these it may be made to 

 combine indirectly. The act of combination between chlorine and 

 other elements is frequently attended by the evolution of so much 

 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, the combination occurs instantly with an 

 explosion. The affinity of chlorine for hydrogen is also demonstrated 

 by its property of decomposing water, ammonia, and many hydro- 

 carbons (compounds of carbon with hydrogen), such as oil of turpen- 

 tine, C 10 H 16 , and others : 



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



NH 3 + 3C1 = 3HC1 + N. 



C 10 H I6 + 16C1 = 16HC1 + IOC. 



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

 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. 



Chlorine water, Aqua chlori, is water saturated with pure chlorine 

 at a temperature of about 10 C. (50 F.). One volume of water 

 absorbs at that temperature about two volumes of chlorine, which is 

 equal to 4 per cent, by weight. Chlorine water is a greenish-yellow 

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

 dark, as otherwise decomposition takes place. 



