228 Dr. Schoenbein on the Action of Hyponitric Acid. 



bined action of bromine and hyponitric acid water will be 

 decomposed, and the hydrobromic and nitric acids formed. 

 Such however seems to be the case, as will be seen from the 

 following statements. 



1. If the fumes of hyponitric acid are made to pass into an 

 aqueous solution of bromine, the brown yellow colour of that 

 fluid will be soon discharged, and its odour of bromine as 

 well as its bleaching power destroyed. The same solution 

 on being mixed either with chlorine or peroxide of lead re- 

 assumes its former colour, bromine being eliminated under 

 those circumstances. It is hardly necessary to add, that an 

 aqueous solution of bromine is also discoloured by nitric acid 

 holding some hyponitric acid dissolved. Having added to 

 aqueous bromine a sufficient quantity of hyponitric acid, 

 the liquid obtained contains no trace either of bromine or 

 hyponitric acid, and is in every respect like a mixture of 

 dilute nitric and hydrobromic acids. From the facts stated, 

 it appears that at the common temperature bromine and 

 hyponitric acid on their being put in contact with water are 

 "transformed into hydrobromic and nitric acids, and accord- 

 ing to the theory of the day, we must account for that reaction 

 by admitting that water is decomposed under the circum- 

 stances mentioned. 



2. A yellow aqueous solution of chlorine treated with hypo- 

 nitric acid in the way indicated under § 1, loses its colour, 

 odour and bleaching power, and has exactly the same pro- 

 perties enjoyed by a mixture of dilute hydrochloric and nitric 

 acids. Hence it follows that hyponitric acid acts upon aque- 

 ous chlorine in the same way as it does upon an aqueous 

 solution of bromine. 



3. If into a bottle, having previously been charged with 

 hydrochloric acid gas, some strong and pure nitric acid is 

 introduced, the latter will, even at a temperature of 15° R. 

 below zero, be rapidly decomposed, chlorine and hyponitric 

 acid being eliminated and water formed. Adding to that mix- 

 ture a sufficient quantity of water, both chlorine and hypo- 

 nitric acid will entirely disappear, i. e. hydrochloric and nitric 

 acids be reformed. 



From the facts above stated, it follows, — 



a. That concentrated nitric and hydrochloric acids decom- 

 pose each other into hyponitric acid, chlorine and water, even 

 at very low temperatures. 



b. That a sufficient quantity of water being present, chlo- 

 rine or bromine, conjointly with hyponitric acid, decompose 

 water (according to the theory of the day), forming nitric and 

 hydrochloric or hydrobromic acid. 



