2 HOW CROPS FEED. 
melts, and gradually decomposes into water and nitrous oxide, or 
‘laughing gas,”’ as represented by the equation :— 
NH, NO, = 2H,O + N,O 
Nitric acid and the nitrates act as powerful oxidizing 
agents, i. e., they readily yield up a portion or all their 
oxygen to substances having strong affinities for this ele- 
ment. If, for example, charcoal be , warmed with strong 
nitric acid, it is rapidly acted upon and converted into 
carbonic acid. If thrown into melted nitrate of soda or 
saltpeter, it takes fire, and is violently burned to carbonic 
acid. Similarly, sulphur, phosphorus, and most of the 
metals, may be oxidized by this acid. 
When nitric acid oxidizes other substances, it itself loses. 
oxygen and suffers reduction to compounds of nitrogen,. 
containing less oxygen. Some of these compounds require 
notice, 
Nitric Oxide, NO.— When nitric. acid somewhat diluted 
with water acts upon metallic copper, a gas is evolved, 
which, after washing with water, is colorless and permanent. 
It is nitric oxide. By exposure to air it unites with oxy- 
gen, and forms red, suffocating fumes of nitric peroxide, 
or, if the oxygen be not in excess, nitrous acid is formed, 
Nitric Peroxide, (hyponitric acid,), NO,, appears as a 
dark yellowish-red gas when strong nitric acid is poured 
upon copper or tin exposed to the air. It is procured in 
a state of purity by: strongly heating nitrate of lead: by. 
a cold approaching zero of Fahrenheit’s thermometer, it 
may be condensed to a yellow liquid or even solid. 
Nitrous Acid, (anhydrous,) N,O,, is produced when 
nitric peroxide is mixed with water at a low temperature, 
nitric acid being formed at the same time. 
iq, Nitrous acid, 
anhydrous. 
4NO, + H,O = 2NHO, + N, O, 
It may be ‘procured as a blue liquid, which boils at the 
freezing point of water. 
Nitric peroxide. Water. Nitric aci 
