16 Taylor, Hypoiodons Acid and Hypoiodites. 



dency to decompose the remaining hypoiodite counter- 

 acted by the presence of the alkali. Then there is also 

 the further consideration that apparently hypoiodous acid 

 can only have about one-half the total bleaching power 

 that a hypoiodite will have, because, as soon as any of 

 it does bleach, it produces hydriodic acid, which would 

 immediately decompose an equivalent amount of the 

 remaining hypoiodous acid. (In one comparative experi- 

 ment that I made, the bleaching power of the free acid 

 was almost exactly half that of an equal volume of the 

 same iodine solution to which soda had been added. 

 But the bleaching continued for two hours, so that the 

 effect would be complicated by the spontaneous decom- 

 position of the free acid.) 



When a little alkali is added to the hypoiodous acid 

 prepared in this way, the solution behaves almost exactly 

 like Schonbein's solutions. It bleaches strongly, and 

 some determinations I have made with the standard 

 indigo solution gave a bleaching action equivalent to 

 80^ of the iodine used, that is, representing 40 out 

 of a possible 50 / o of iodine existing as hypoiodous 

 acid. This result again is confirmed by experiments by 

 Schwicker's method, only in the case of this solution, 

 when it is neutralised by an alkali, it forms nothing else 

 but hypoiodite, and consequently the addition of soda- 

 water simply liberates hypoiodous acid, and there is no 

 separation of iodine. In order to complete the deter- 

 mination potassium iodide has to be added, when there is 

 an immediate liberation of iodine. A determination by 

 this method, which is probably more accurate than the 

 bleaching method, gave liberated iodine equal to 90 % 

 of that originally used, so that 45 out of a possible 50^ 

 of iodine existed in the solution as hypoiodous acid. 



The hypoiodous acid solution to which a little alkali 

 has been added gives a precipitate with cobalt solution, 



