8 Taylor, Hypoiodous Acid and Hypoioditcs. 



needed to decompose each other (5H I + H I 5 =3H 2 O 

 +3I2). 



I have made similar bleaching solutions by using lime- 

 water and baryta-water with aqueous iodine, and in 

 nearly all respects these resemble Schonbein's solutions,, 

 there being perhaps a little difference in their stability in 

 favour of the sodium and potassium compounds. They 

 are all decomposed on boiling. 



I have further found that, by using a little very finely 

 divided (preferably precipitated) iodine with the aqueous 

 iodine and then adding the alkali, very much stronger 

 solutions may be prepared. A solution made in this way 

 bleaches large quantities of indigo, and gives further- 

 reactions which add very strongly to the evidence that 

 these solutions contain hypoiodites. Thus they give a 

 black precipitate (on standing) with a cobalt solution ; an 

 immediate dark brown precipitate with a solution of a 

 manganous salt; and with lead salts a precipitate which 

 manifestly contains a considerable amount of the brown 

 peroxide of lead. Also these strong solutions give an 

 immediate and copious evolution of oxygen with hydrogen 

 dioxide. In these reactions the solution acts exactly as 

 the corresponding hypochlorites and hypobromites do. 

 The dilute solutions made with aqueous iodine naturally 

 do not give these reactions so satisfactorily unless large 

 quantities are used. On the other hand, the stronger 

 solutions would not be so suitable for the quantitative 

 experiments as the more dilute ones. 



The solution made with iodine water and not too 

 much alkali gives with nitrate of silver a precipitate 

 which is quite distinct from the ordinary precipitated 

 hydrate of silver, having a sort of dark buff colour. Of 

 course the precipitate must contain silver iodide and 

 probably also some hydrate, as the original liquid must 

 of necessity be somewhat alkaline ; but it probably also 



