N I T
N I T
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point or mode of combination of azot at whichthe deoxygenation of nitrous oxyd would havea tendency to Hop, a-s nitrous oxyd itlelf iswith regard to nitrous gas; and nitrous gaswith regard to nitric acid.
Two more decompofitions of nitrous oxydrequire to be noticed, that by the eleftric fparkfimply, and that by hydrogen afliiled by theelectric fpark.
Dr. Prieftley found that on taking the electricfpark frequently in nitrous oxyd, no perceptiblechange was produced in its quantity, but it wasbecome immifcible with water.
The fame experiment was repeated by Mr.Davy with accuracy, and by palling 150 Itrong■ftrokes through 7 ten-grain meafures of purenitrous oxyd, after which "it was reduced to 6meafures. This refulue mixed with 6 meafuresof nitrous gas and a little water, gave red fumes,and a diminution of bulk took place nearly equalto that which common air would produce with.nitrous gas. In another experiment the famequantity of nitrous oxyd was reduced to 6Jmeafures, and red cabbage juice faturated withnitrous oxyd, and rendered green by alkali, hadits red colour reftored in the procefs, thusfhewing the production of an acid, whichcould be no other than the nitric. The effectof electrization therefore is entirely to decom-pofe the nitrous oxyd, to condenfe a largerproportion of the oxygen into one portion ofthe azot and convert it into nitrous acid, andconfequently to leave a fmaller proportion ofoxygen in the remainder, and thus produce thegas refembling atmofpheric air.
A fimilar change is produced by tranfmitting-nitrous oxyd through a red hot glazed por-celain tube.
When hydrogen and nitrous oxyd are mixedand the electric fpark paffed through, theyexplode with confiderable violence, and with abright red light. The bulk of the refidue isalways much lefs than the united bulk of thegaffes before the explofion, but the exacl quan-tity (the gaffes being pure) depends on theproportion in which the two are mixed. Thenature of the refidue alfo varies according to
the proportion of the gaffes: where the hydrogenis to the nitrous gas as 50 to 40, the decompo-fition is perfect:, the refidue is entirely azot,about a fourth more in bulk than the nitrousoxyd, and confequently is not changed bynitrous gas nor abforbed by water. As all thehydrogen difappears, it muft unite with theoxygen of the nitrous oxyd to form water, andno traces of nitric acid can be perceived. Wherethe hydrogen is lefs in quantity than the nitrousoxyd, the effeft feems to be that of the formerinftance combined with that produced by thefimple ele£trization of the nitrous oxyd, fo thatthe produfts are, water, azot, nitric acid, anda mixture of azot and oxygen.
The decompofition of nitrous oxyd by char-coal, hydrogen, and phol'phuretted hydrogen,were all found by Mr. Davy’s experiments tooffer a very fatisfaCtory agreement in the refults,confidering the difficulty of analyfis. Thefmalleft quantity of oxygen found in the gaswas 35 in 100, by weight, and the large!! 39.If the mean between the two is taken, it may-be concluded that 100 grains of it are compofedof about 63 of azot and 37 oxygen; and that100 cubic inches weigh 50 grs. at 55° tempera-ture, and 30 inches of atmofpheric preffure.
We may conclude this article with the tableof the combinations of azot given by Mr. Davy,which may be confidered on the whole as theneareft approximations to accuracy which wepoffefs.
xoo cubic inches at 55 0 Therm, and 30 Bar.
grains
Of azot ----- weigh 30.04
Oxygen - - - - - - 35.06
Atmofpheric air - - - 31.10
Nitrous oxyd - - - - 50.20
Nitrous gas ----- 34.26
Gaffeous nitric acid - - 76.00
Compofition of 100 grains of the abovefubftances.