368 CHLORINE. 



The gas is of a pale yellow colour, very similar to chlorine. 

 It is composed of 2 volumes of chlorine and 1 volume of oxy- 

 gen, condensed into 2 volumes, and is resolved by a slight 

 elevation of temperature into its constituent gases. This de- 

 composition is attended with an explosion of such violence as 

 to project the jar from the trough, but not to break it to pieces, 

 and may occur on transferring the gas from one jar into another. 

 Water dissolves about 100 volumes of this gas. 



The original solution of hypochlorous acid may be distilled, 

 but much of the acid is decomposed unless the operation be 

 conducted in vacuo. It is then obtained as a transparent liquid 

 of a slightly yellow colour. It displaces the carbonic acid of 

 alkaline carbonates, but has not much analogy to other acids. 

 Its taste is extremely strong and acrid, but not sour, and its 

 odour penetrating and different from, although somewhat similar 

 to chlorine. It attacks the epidermis like nitric acid, and is ex- 

 ceedingly corrosive. It bleaches instantly, like chlorine, and is 

 a powerful oxidizing agent. When concentrated it is exceed- 

 ingly unstable, small bubbles of chlorine gas being sponta- 

 neously evolved and chloric acid formed. This decomposition 

 is promoted by the presence of angular bodies, such as pounded 

 glass, and also by heat and light. 



Of the elementary bodies, hydrogen has no action upon hypo- 

 chlorous acid. Sulphur, selenium, phosphorus and arsenic 

 act upon it with great energy, and are all of them raised to their 

 highest degree of oxidation, with the evolution of chlorine gas ; 

 selenium even being converted into selenic acid, although it is 

 only converted into selenious acid by the action of nitric acid. 

 Iodine is also converted into iodic acid. Iron filings decom- 

 pose it immediately and chlorine comes off. Copper and 

 mercury combine with both elements of the acid and form 

 oxichlorides. Many other metals are not acted upon by it, 

 unless another acid be present, such as zinc, tin, antimony and 

 lead. Silver has a different action upon hypochlorous acid 

 from that of most bodies, combining with its chlorine and caus- 

 ing an evolution of oxygen gas. Hydrochloric and hypochlorous 

 acids mutually decompose each other, water being formed, and 

 chlorine liberated ; the presence of soluble chlorides is equally 

 incompatible with the existence of hypochlorous acid. 



Hypochlorites. The direct combination of hypochlorous 

 acid with powerful bases is accompanied by heat, which is apt 



