NITRIC PEROXIDE. 



varied conditions, both with regard to electric energy, and 

 pressure and the relative proportions of the gases. The 

 important point is the existence of the limits, as a necessary 

 consequence of the two antagonistic reactions. 



The action of water on nitric peroxide deserves attention. 



If the water be in small quantity and the nitric peroxide 

 liquid, we obtain, as is well known, at a low temperature, 

 anhydrous nitrogen trioxide 



4N0 2 + H 2 = N 2 3 + 2HX0 3 . 



In the presence of a large quantity of water, nitric peroxide 

 gas, acting gradually, is completely absorbed with the formation 

 of hydrated nitric acid and nitrogen trioxide 



4N 2 + NH 2 = 2HN0 3 dilute + N 2 3 dilute. 



This reaction liberates 7*7 Cal. for N0 2 = 46 grms. 



But liquid nitric peroxide, in presence of the same quantity 

 of water, gives rise, generally speaking, to some nitric oxide, 

 according to the following reactions, which refer to quantities 

 of substances of which the proportion is variable with the 

 conditions of contact : 



3N0 2 + ^H 2 = 2HN0 3 dilute + NO. 



This reaction, which may be limited almost to nil when contact 

 is gradually effected, liberates, after it takes place, + 4*8 for 

 N0 2 . 



The following experiment is easy of repetition, and clearly 

 shows both modes of decomposition of nitric peroxide under the 

 influence of water. Into a rather large tube, closed at one end 

 and formed at the other into a funnel, is poured a little liquid 

 nitric peroxide, which, in order to drive out the air, is brought 

 into a state of ebullition, leaving only an insignificant quantity 

 of liquid. The tube is then hermetically sealed. Liquid peroxide 

 is then poured into a similar but much smaller tube ; the air is 

 expelled in the same way by boiling, and the tube is closed. 

 After cooling, the large tube, being opened over water, fills 

 completely, owing to the total decomposition of the peroxide 

 into nitrogen trioxide and nitric acid. On the other hand, the 

 small tube is only partly filled, owing to the formation of nitric 

 oxide. 



The difference between these two reactions appears to be 

 due to the slight stability of hydrated nitrogen trioxide above 

 defined (p. 197). If the peroxide has at the outset enough water 

 to form hydrated nitrogen trioxide without decomposition the 

 absorption is complete. This is the case with gaseous peroxide 

 and water gradually reacting over a large surface. But if it 

 comes into contact at one point with too small a quantity of 

 water the acid will be partly decomposed with formation of 



