ATMOSPnEi:i(; air a>; tiie food op plants. 73 



When nitric peroxiJe is ])ut in cont:icL with solutions 

 of an alkali, there lesults a mixture of nitrate and nitrite 

 of the alkali. 



JVitric Hydnde of Nitrate of Nitrite of -rp-^^g^ 

 peroxide. potash. potash. i)otash. 



2 NO, + 2 IIKO = NKO3 + NKO, + II, O 



Nitrite of Ammonia, NH^ NO., is known to the chem- 

 ist as a white crystalline solid, very soluble in water. 

 When its concentrated aqueous solution is gently heated, 

 the salt is gradually resolved into water and nitrogen gas. 

 This decomposition is represented by the following equa- 

 tion : 



NH, NO, = 2 H,0 + 2 N 



This decomposition is, however, not complete, A por- 

 tion of ammonia escapes in the vapors, ami nitrous acid 

 accumulates in the residual liquid. (Pettenkofer.) Addi- 

 tion of a strong acid facilitates decomposition; an alkali 

 retards it. When a dilute solution, 1 : 500, is boiled, but 

 a small portion of the salt is decomposed, and a part of it 

 is found in the distillate. Very dilute solutions, 1 : 100,000, 

 may be boiled without suifering any alteration whatever. 

 (Schuyen.) 



Schonbein and others have (erroneously?) supposed that 

 nitrite of ammonia is generated by the direct union of 

 nitrogen and water. Nitrite of ammonia may exist in the 

 atmosphere in minute quantity. 



Nitrites of pot i'<h and soda may be procured by strongly 

 heating the corresponding nitrates, Avhereby oxygen gas is 

 expelled. 



The Hutuai Convertibility of Nitrates and Nitrites is 



illustrated by various statements a'jvady made. There 

 are, in fact, numerous substances which reduce nitrates to 

 nitrites. According to Schonbein, {Jour. Prakt. Ch., 84, 

 207,) this reducing effect is exercised by the albuminoids, 

 by starch, glucose, and milk-sugar, but not by cane-sugar, 

 4 



