I attempted in different modes to combine _nitrous_ acids with
ammoniac, so as to form the salts which have been supposed to exist,
and called _nitrites_ of ammoniac; but without success.
I first decomposed a solution of carbonate of ammoniac by dilute olive
colored acid; but in this process, though no heat was generated,
yet all the nitrous gas appeared to be liberated with the carbonic
acid.[75] I then combined a small quantity of nitrous gas, with a
solution of nitrate of ammoniac. But after evaporating this solution
at 70°-80°, I could not detect the existence of nitrous gas in the
solid salt; it was given out during the evaporation and crystalisation,
and formed into nitrous acid by the oxygene of the atmosphere. I
likewise heated nitrate of ammoniac to different degrees, and partially
decomposed it, to ascertain if in any case the acid was phlogisticated
by heat: but in no experiment could I detect the existence of
_nitrous_ acid in the heated salt, when it had been previously
perfectly neutralised.
[75] When nitrous gas exists in neutro-saline solutions, they are
always colored more or less intensely, from yellow to olive, in
proportion to the quantity combined with them.
When nitrate of ammoniac, indeed, with excess of nitric acid, is
exposed to heat, the superabundant nitric acid becomes phlogisticated,
and is then liberated from the salt, which remains neutral.[76]
[76] Hence a nitrate of ammoniac with excess of acid, when exposed to
heat, first becomes yellow, and then white.
We may therefore conclude that nitrous gas has little or no affinity
for solid nitrate of ammoniac, and that no substance exists to which
the name _nitrite_ of ammoniac can with propriety be applied.