ON AQUA REGIA AND HYPOSULPHURIC ACID. 209 
ON HYPONITRIC ACID CONSIDERED AS AN OXIDISING AGENT. 
20. We have just seen that the action of hydrochloric 
acid upon nitric acid becomes embarrassed as soon as the 
latter is reduced to the stage of nitrous acid. This is mani- 
festly owing to the circumstance that the oxygen is in a 
more intimate state of combination in the latter acid, than 
in nitric and hyponitric acids. Nitrous acid is, therefore, 
the most stable, and, consequently, of the three stages 
of oxidation of nitrogen, the least powerful oxidating 
agent. 
This inference, drawn from the reaction between hydro- 
chloric, nitric, and hyponitric acids placed in concentrated 
sulphuric acid, is far from coinciding with that which Millon 
concluded from his experiments. According to this chemist 
the process of oxidation by nitric acid is in general the fol- 
lowing: — nitrous acid is formed first, and with this nitrite 
of copper, mercury, silver, &c, produced ; these salts are 
again destroyed by the nitric acid, and this destruction 
giving rise to the formation of oxide of nitrogen, the latter 
body on coming into contact with the nitric acid reforms the 
nitrous acid, the metal is then attacked again by this acid, 
and the salt formed destroyed, and so on in succession. 
acid (vide the details of my experiments;) not to combine with the ele- 
ments of water; but to furnish nitrates and chlorides with the metalloids; 
to attack gold, and to explode with silver reduced to powder; to act, 
but slowly , however, on potassium; with the powder of antimony or ar- 
senic to produce intense phenomena of light and heat, without producing 
similar phenomena with fused phosphorus [Annalen der Chemie und Phar- 
macies xlviii. p. 202, and Traite de Chimie Generale, fyc, par A. Baudri- 
mont, i. p. 616.) 
If the French chemist, instead of having employed the raw products 
of commerce, had operated with dry hydrochloric acid, and if he had 
taken care to dry the chloronitrous gas, and to ascertain the absence of 
hydrochloric acid, it might have been possible to form an opinion on 
the merits of his work, the data of which require more minute re- 
searches. 
VOL. XI. NO. III. 
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