CHLORINE. 101 



Properties. Chlorine is a greenish-yellow gas, having a dis- 

 agreeable 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 four atmospheres. 



Chemically, the properties of chlorine are well marked, and 

 there are but few elements which have as strong an affinity for 

 other elements 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 combina- 

 tion between chlorine and other elements is frequently attended 

 by the evolution of so much heat that light is produced, or, in 

 other w r ords, combustion takes place. Thus hydrogen, phos- 

 phorus, and many metals burn easily in chlorine. The affinity 

 between chlorine and hydrogen is very great, 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 the direct sunlight, the combination occurs 

 instantly with an explosion. The affinity of chlorine for hy- 

 drogen is also demonstrated by its property of decomposing 

 water, ammonia, and many hydrocarbons (compounds of carbon 

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



H 2 + 2C1 = 2HC1 + ; 



NH 3 + 3C1 = 3HC1 + N ; 



C 10 H 16 + 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. One volume of water absorbs at 

 that temperature about two volumes of chlorine, which is equal 

 to 0.4 per cent, by weight. Chlorine water is a greenish-yellow 



