V> NEWY9RK. .J 

 MaJiclicstcr Memoirs, Vol. xlvii. (1902), No. I. 



I. On the Reaction of Iodine with Mercuric Oxide 

 in Presence of Water. 



By R. L. Taylor, F.C.S. 



Received a7id read October 1th, ig02. 



In a former paper, read in 1897 before this Society 

 {Memoirs, Vol. 41, No. 8), on " Hypoiodous Acid and 

 Hypoiodites," I described some experiments which I had 

 made on the preparation of hypoiodous acid by the action 

 of iodine in presence of water on mercuric oxide. My 

 experiments led me to the conclusion that, when an 

 aqueous solution of iodine (i part in 5,000) is shaken up 

 with precipitated mercuric oxide, the reaction proceeds 

 exactly as it does with chlorine and bromine under similar 

 circumstances, with the production of hypoiodous acid, 

 probably according to the following equation : — 

 HgO + 4I + H„0 = Hgl, + 2 HOI. 

 If the reaction proceeds according to this equation, 

 one-half of the total amount of iodine employed is con- 

 verted into hypoiodous acid (or else a hypoiodite). I 

 found that, when the liquid was filtered immediately after 

 shaking, the iodine present in the filtrate as hypoiodous 

 acid amounted to from 40 to 45 per cent, of that 

 originally used,— that is, from 80 to 90 per cent, of the 

 possible amount. I also pointed out that, using even such 

 an excessively dilute solution as i part in 5,000, the 

 hypoiodous acid was extremely unstable, and that the 

 filtrate rapidly began to turn brown, owing to the libera- 

 tion of iodine. With larger amounts of iodine (in propor- 

 tion to the water) the rate of decomposition was much 

 greater— so rapid, indeed, as to make it difficult to deter- 

 mine the amount of hypoiodous acid which the filtrate 

 contained. 



December i^th, igo2. 





