Nitric Sentence Examples

It is an indigo-blue powder, soluble in hydrochloric acid, but insoluble in dilute nitric and sulphuric acids.

Iridium tetrachloride, IrC1 41 is obtained by dissolving the finely divided metal in aqua regia; by dissolving the hydroxide in hydrochloric acid; and by digesting the hydrated sesquichloride with nitric acid.

It decomposes steam at a red heat, and slowly dissolves in dilute hydrochloric and sulphuric acids, but more readily in nitric acid.

It is somewhat readily oxidized; nitric acid gives carbonic and oxalic acids, and chromic acid, carbonic and acetic acids.

Heated with sulphuric acid and with nitric acid it is oxidized to boric acid, whilst on fusion with alkaline carbonates and hydroxides it gives a borate of the alkali metal.

Brugnatelli, who found in 1798 that if silver be dissolved in nitric acid and the solution added to spirits of wine, a white, highly explosive powder was obtained.

Cadmium nitrate, Cd(N03)2.4H20, is a deliquescent salt, which may be obtained by dissolving either the metal, or its oxide or carbonate in dilute nitric acid.

It is soluble in dilute nitric acid, and in concentrated sulphuric acid; in the XVIII.

Molybdenum trioxide, Mo03, is prepared by oxidizing the metal or the sulphide by heating them in air, or with nitric acid.

The molybdates may be recognized by the fact that they give a white precipitate on the addition of hydrochloric or nitric acids to their solutions, and that with reducing agents (zinc and sulphuric acid) they give generally a blue coloration which turns to a green and finally to a brown colour.

It is a yellow amorphous powder which is soluble in dilute alkalis, the solution on acidification giving an hydroxide, C1 4 Mo 3 (OH) 2, which is soluble in nitric acid, and does not give a reaction with silver nitrate.

It is easily soluble in hot nitric acid.

It is readily oxidized by nitric acid, and when strongly heated_ in a current of hydrogen is reduced to the metallic condition.

Nitro-phenols are readily obtained by the action of nitric acid on phenol.

By the action of dilute nitric acid; orthoand para-nitrophenols are obtained, the ortho-compound being separated from the para-compound by distillation in a current of steam.

Two oxides of germanium are known, the dioxide, GeO2, being obtained by roasting the sulphide and treatment with nitric acid.

Amongst endothermic compounds may be noted hydriodic acid, HI, acetylene, C 2 H 2, nitrous oxide, N 2 O, nitric oxide, NO, azoimide, N 3 H, nitrogen trichloride, NC1 3.

A mixture of carbon bisulphide vapour and nitric oxide burns with a very intense blue-coloured flame, which is very rich in the violet or actinic rays.

These are washed with ammonium chloride until the filtrate is colourless, ignited, fused with caustic potash and nitre, the melt dissolved in water and nitric acid added to the solution until the colour of potassium ruthenate disappears.

The insoluble residue contains a mixture of two sulphides, one of which is converted into the sulphate by nitric acid, whilst the other (a crystalline solid) is insoluble in acids.

Again, in nitrous oxide we have a compound of 8 parts by weight of oxygen and 14 of nitrogen; in nitric oxide a compound of 16 or 8 X 2 parts of oxygen and 1 4 of nitrogen; in nitrous anhydride a compound of 24 or 8 X 3 parts of oxygen and 14 of nitrogen; in nitric peroxide a compound of 3 2 or 8 X 4 parts of oxygen and 14 of nitrogen; and lastly, in nitric anhydride a compound of 4 o or 8 X 5 parts of oxygen and 14 of nitrogen.

For example take the oxides of nitrogen, N 2 0, NO, N 2 0 3, NO 2, N 2 0 5; these are known respectively as nitrous oxide, nitric oxide, nitrogen trioxide, nitrogen peroxide and nitrogen pentoxide.

Among the Arabian and later alchemists we find attempts made to collate compounds by specific properties, and it is to these writers that we are mainly indebted for such terms as "alkali," " sal," &c. The mineral acids, hydrochloric, nitric and sulphuric acids, and also aqua regia (a mixture of hydrochloric and nitric acids) were discovered, and the vitriols, alum, saltpetre, sal-ammoniac, ammonium carbonate, silver nitrate (lunar caustic) became better known.

Glauber showed how to prepare hydrochloric acid, spiritus salis, by heating rock-salt with sulphuric acid, the method in common use to-day; and also nitric acid from saltpetre and arsenic trioxide.

Sulphuretted hydrogen and nitric oxide were discovered at about the same time.

Thus, he interpreted the interaction of benzene and nitric acid as C6H61-HN03 = C 6 H 5 NO 2 +H 2 0, the "residues" of benzene being C 6 H 5 and H, and of nitric acid HO and N02.

This compound is readily oxidized to benzoic acid, C 6 H 5 000H, the aromatic residue being unattacked; nitric and sulphuric acids produce nitro-toluenes, C6H4 CH3 N02j and toluene sulphonic acids, C 6 H 4 CH 3 SO 3 H; chlorination may result in the formation of derivatives substituted either in the aromatic nucleus or in the side chain; the former substitution occurs most readily, chlor-toluenes, C 6 H 4 CH 3 Cl, being formed, while the latter, which needs an elevation in temperature or other auxiliary, yields benzyl chloride, C 6 H 5 CH 2 C1, and benzal chloride, C 6 11 5 CHC1 2.

Substitution of the Benzene Ring.-As a general rule, homologues and mono-derivatives of benzene react more readily with substituting agents than the parent hydrocarbon; for example, phenol is converted into tribromphenol by the action of bromine water, and into the nitrophenols by dilute nitric acid; similar activity characterizes aniline.

If it possesses an alkaline or acid reaction, it must be tested in the first case for ammonia, and in the second case for a volatile acid, such as sulphuric, nitric, hydrochloric, &c.

The metallic film is tested with 20% nitric acid and with bleaching-powder solution.

Small portions should be successively tested with waterMilute hydrochloric acid, dilute nitric acid, strong hydrochloric acid, and a mixture of hydrochloric and nitric acids, first in the cold and then with warming.

Silver chloride goes into solution, and may be precipitated by dilute nitric acid.

The residue from the ammonium sulphide solution is warmed with dilute nitric acid.

Similarly, normal solutions of hydrochloric and nitric acids can be prepared.

The first class includes those substances which require no preliminary treatment, and comprises the amides and ammonium compounds, pyridines, quinolines, alkaloids, albumens and related bodies; the second class requires preliminary treatment and comprises, with few exceptions, the nitro-, nitroso-, azo-, diazoand amidoazo-compounds, hydrazines, derivatives of nitric and nitrous acids, and probably cyanogen compounds.

The halogens may be estimated by ignition with quicklime, or by heating with nitric acid and silver nitrate in a sealed tube.

On boiling with concentrated nitric acid it yields picric acid.

The first product of the reaction is nitric oxide, which on cooling with the residual gases produces nitrogen peroxide.

If the gas be mixed with the vapour of carbon disulphide, the mixture burns with a vivid lavender-coloured flame Nitric oxide is soluble in solutions of ferrous salts, a dark brown solution being formed, which is readily decomposed by heat, with evolution of nitric oxide.

Nascent hydrogen reduces it to hydroxylamine (q.v.), whilst solutions of hypochlorites oxidize it to nitric acid.

He then tried the direct combination of nitric oxide with liquid nitrogen peroxide.

Nitrogen peroxide, NO 2 or N204, may be obtained by mixing oxygen with nitric oxide and passing the red gas so obtained through a freezing mixture.

It converts many metallic oxides into mixtures of nitrates and nitrites, and attacks many metals, forming nitrates and being itself reduced to nitric oxide.

It may also be obtained by distilling nitric acid over phosphorus pentoxide.

It dissolves in water, forming nitric acid.

Bromine oxidizes it to nitric acid, but the reaction is not quantitative.

In acid solution, potassium permanganate oxidizes it to nitric acid, but in alkaline solution only to nitrous acid.

The silver salt is a bright yellow solid, soluble in dilute sulphuric and nitric acids, and may be crystallized from concentrated solutions of ammonia.

The calcium salt, CaN 2 O 2.4H 2 O, formed by the action of calcium chloride on the silver salt in the presence of a small quantity of nitric acid, is a lustrous crystalline powder, almost insoluble in water but readily soluble in dilute acids.

These methods have been purely chemical (either gravimetric or volumetric), physical (determinations of the density of nitrogen, nitric oxide, &c.) or physicochemical.

It is a very stable compound, chlorine, concentrated nitric acid and hydriodic acid having no action upon it.

Dilute nitric acid readily dissolves the metal, with formation of nitrate Pb(N03)2.

It is also obtained by passing chlorine into a suspension of lead oxide or carbonate, or of magnesia and lead sulphate, in water; or by treating the sesquioxide or red oxide with nitric acid.

Heating or exposure to sunlight reduces it to the red oxide; it fires when ground with sulphur, and oxidizes ammonia to nitric acid, with the simultaneous formation of ammonium nitrate.

It oxidizes a manganese salt (free from chlorine) in the presence of nitric acid to a permanganate; this is a very delicate test for manganese.

Lead fluoride, PbF2, is a white powder obtained by precipitating a lead salt with a soluble fluoride; it is sparingly soluble in water but readily dissolves in hydrochloric and nitric acids.

It dissolves in strong nitric acid with the formation of the nitrate and sulphate, and also in hot concentrated hydrochloric acid.

Lead nitrate, Pb(N03)2, is obtained by dissolving the metal or oxide in aqueous nitric acid; it forms white crystals, difficultly soluble in cold water, readily in hot water and almost insoluble in strong nitric acid.

The beautiful yellow precipitate is little soluble in dilute nitric acid, but soluble in caustic potash.

But the most delicate precipitant for lead is sulphuretted hydrogen, which produces a black precipitate of lead sulphide, insoluble in cold dilute nitric acid, less so in cold hydrochloric, and easily decomposed by hot hydrochloric acid with formation of the characteristic chloride.

Paraldehyde is oxidized by dilute nitric acid, with formation of much glyoxal, (CHO) 2.

It burns on heating in air; and is scarcely attacked by hydrochloric or nitric acids, or by aqua regia; it is soluble in warm concentrated sulphuric acid.

Aromatic Nitro Compounds.-The aromatic nitro compounds are generally obtained by the direct action of nitric acid.

In one process the purified ore is disintegrated with hot nitric acid to produce nitrates, which are then converted into sulphates by evaporation with sulphuric acid.

It is obtained as fine lemon yellow deliquescent prisms by evaporating a solution of any of the oxides in nitric acid.

It is insoluble in water and in nitric acid and apparently so in hydrochloric acid; but if heated with this last for some time it passes into a compound, which, after the acid mother liquor has been decanted off, dissolves in water.

Metastannic acid is distinguished from orthostannic acid by its insolubility in nitric and sulphuric acids.

On oxidation with potassium permanganate it gives homovanillin, vanillin, &c.; with chromic acid in acetic acid solution it is converted into carbon dioxide and acetic acid, whilst nitric acid oxidizes it to oxalic acid.

Pelouze in 1838, who observed that when paper or cotton was immersed in cold concentrated nitric acid the materials, though not altered in physical appearance, became heavier, and after washing and drying were possessed of self-explosive properties.

Bottger of Frankfort and Otto and Knop, all of whom added to our knowledge of the subject, the last-named introducing the use of sulphuric along with nitric acid in the nitration process.

The products of the action of nitric acid on cellulose are not nitro compounds in the sense that picric acid is, but are nitrates or nitric esters.

Guncotton is made by immersing cleaned and dried cotton waste in a mixture of strong nitric and sulphuric acids.

The gaseous mixture obtained by burning guncotton in a vacuum vessel contains steam, carbon monoxide, carbon dioxide, nitrogen, nitric oxide, and methane.

Under very great pressures carbon monoxide, steam and nitrogen are the main products, but nitric oxide never quite disappears.

Strong sulphuric acid in contact with it liberates first nitric acid and later oxides of nitrogen, leaving a charred residue or a brown solution according to the quantity of acid.

Guncottons are examined for degree of nitration by the nitrometer, in which apparatus they are decomposed by sulphuric acid in contact with mercury, and all the nitrogen is evolved as nitric oxide, NO, which is measured and the weight of its contained nitrogen calculated.

They all contain albumen and throw down a precipitate with heat and nitric acid.

When the solution in the strong acid is allowed to stand, some nitric acid is first evolved, and as the temperature rises this is followed by a general decomposition of the substance, though not necessarily an explosive one.

Shaken with mercury and sulphuric acid, nitroglycerin yields its nitrogen as nitric oxide; the measurement of the volume of this gas is a convenient mode of estimating nitroglycerin.

Hydriodic acid reduces it to glycerin and nitric oxide.

The former is completely decomposed when fused with caustic potash and the latter by a prolonged boiling with nitric acid.

Aqua Regia, a mixture of nitric and hydrochloric acids, converts all metals (even gold, the "king of metals," whence the name) into chlorides, except only rhodium, iridium and ruthenium, which, when pure, are not attacked.

It is oxidized by nitric acid to d-saccharic and mucic acids; and acetic anhydride gives an octa-acetate.

Styrolene is oxidized by nitric or chromic acids to benzoic acid; reduction gives ethylbenzene; hydrochloric and hydrobromic acids yield a-haloid ethylbenzenes, e.g.

Nitrostyrolene results when styrolene is treated with fuming nitric acid.

Its chief uses are in glass-making to promote fluidity, in metallurgy to oxidize impurities, as a constituent of gunpowder and in pyrotechny; it is also used in the manufacture of nitric acid.

The chief applications of Chile saltpetre are in the nitric acid industry, and in the manufacture of ordinary saltpetre for making gunpowder, ordinary Chile saltpetre being unsuitable by reason of its deliquescent nature, a property, however, not exhibited by the perfectly pure salt.

Its chief applications are as a manure and in the nitric acid industry.

Cold dilute nitric acid dissolves zinc as nitrate, with evolution of nitrous oxide.

At higher temperatures, or with stronger acid, nitric oxide, NO, is produced besides or instead of nitrous.

It combines directly with the halogens, and dissolves in cold dilute sulphuric acid, in hot strong hydrochloric acid and in aqua regia, but less readily in nitric acid.

It gives the normal sulphate as a yellow, deliquescent, amorphous mass when treated with nitric acid.

Ladenburg, Ber., 1886, 19, p. 783); by heating the esters of nitric acid with alcoholic ammonia at 10o C. (0.

Concentrated nitric acid attacks them violently, producing various oxidation products, but if the amino group be "protected" by being previously acetylated, then nitro derivatives are obtained.

Nitric, hydrochloric and sulphuric acids, all more or less impure, were better studied; and many ethereal oils were discovered.

For example, in the less modern methods for manufacturing nitric acid the vapours were conducted directly into double-necked bottles (bombonnes) immersed in water.

The technology of distillation is best studied in relation to the several industries in which it is employed; reference should be made to the articles COAL-TAR, GAS, PETROLEUM, SPIRITS, NITRIC ACID, &c. (C. E.*)

Strontium nitrate, Sr(N03)2, is obtained by dissolving the carbonate in dilute nitric acid.

Potassium bichromate oxidizes it to malonic acid; nitric acid oxidizes it to oxalic acid; and hydriodic acid reduces it to succinic acid.

Scheele prepared it by oxidizing sugar with nitric acid, and showed it to be identical with the acetosellic acid obtained from wood-sorrel.

It is insoluble in hydrochloric, nitric and sulphuric acids, but dissolves in aqua regia - a mixture of hydrochloric and nitric acids - and when very finely divided in a heated mixture of strong sulphuric acid and a little nitric acid; dilution with water, however, precipitates the metal as a violet or brown powder from this solution.

The metal is soluble in solutions of chlorine, bromine, thiosulphates and cyanides; and also in solutions which generate chlorine, such as mixtures of hydrochloric acid with nitric acid, chromic acid, antimonious acid, peroxides and nitrates, and of nitric acid with a chloride.

In the " dry " methods the silver is converted into sulphide or chloride, the gold remaining unaltered; in the " wet " methods the silver is dissolved by nitric acid or boiling sulphuric acid; and in the electrolytic processes advantage is taken of the fact that under certain current densities and other circumstances silver passes from an anode composed of a gold-silver alloy to the cathode more readily than gold.

The sulphur and litharge, or Pfannenschmied, process was used to concentrate the gold in an alloy in order to make it amenable to " quartation," or parting with nitric acid.

The separation of gold from silver in the wet way may be effected by nitric acid, sulphuric acid or by a mixture of sulphuric acid and aqua regia.

Parting by nitric acid is of considerable antiquity, being mentioned by Albertus Magnus (13th cent.), Biringuccio (1540) and Agricola (1556).

It is now rarely practised, although in some refineries both the nitric acid and the sulphuric acid processes are combined, the alloy being first treated with nitric acid.

The operation may be conducted in vessels of glass or platinum, and each pound of granulated metal is treated with a pound and a quarter of nitric acid of specific gravity 1.32.

The silver is quite free from gold, and the gold after boiling with nitric acid has a fineness of over 999.

The basic nitrate is the salt generally prepared, and, in general outline, the process consists in dissolving the metal in nitric acid, adding water to the solution, boiling the precipitated basic nitrate with an alkali to remove the arsenic and lead, dissolving the residue in nitric acid, and reprecipitating as basic nitrate with water.

Hampe prepared chemically pure bismuth by fusing the metal with sodium carbonate and sulphur, dissolving the bismuth sulphide so formed in nitric acid, precipitating the bismuth as the basic nitrate, redissolving this salt in nitric acid, and then precipitating with ammonia.

Bismuth combines directly with the halogens, and the elements of the sulphur group. It readily dissolves in nitric acid, aqua regia, and hot sulphuric acid, but tardily in hot hydrochloric acid.

The normal nitrate, Bi(N03)3.5H20, is obtained in large transparent asymmetric prisms by evaporating a solution of the metal in nitric acid.

It is easily soluble in nitric acid.

The blackish brown sulphide precipitated from bismuth salts by sulphuretted hydrogen is insoluble in ammonium sulphide, but is readily dissolved by nitric acid.

This second group may be divided into a-Barbaloins, obtained from Barbadoes aloes, and reddened in the cold, and Barbaloins, obtained from Socotrine and Zanzibar aloes, reddened by ordinary nitric acid only when warmed, or by fuming acid in the cold.

Tellurous acid, H 2 TeO 3, is obtained when the tetrachloride is decomposed by water, or on dissolving tellurium in nitric acid and pouring the solution into water.

Caesium nitrate, CsNO 3, is obtained by dissolving the carbonate in nitric acid, and crystallizes in glittering prisms, which melt readily, and on heating evolve oxygen and leave a residue of caesium nitrite.

Picric acid can also be obtained from it by first treating acetylene with sulphuric acid, converting the product into phenol by solution in potash and then treating the phenol with fuming nitric acid.

The barium salt is extracted by water and boiled with nitric acid, when the osmium volatilizes in the form of its tetroxide.

After fusion, the mass is finely powdered and treated with cold dilute hydrochloric acid; and when action has finished, nitric and sulphuric acids are added, the precipitated barium sulphate removed, the liquid distilled and the osmium precipitated as sulphide.

In the massive state it is insoluble in all acids, but when freshly precipitated from solutions it dissolves in fuming nitric acid.

Nitric acid and lower nitrogen oxides are present, being formed by electrical discharges, and by the oxidation of atmospheric ammonia by ozone.

Orthophosphoric acid, H3P04, a tribasic acid, is obtained by boiling a solution of the pentoxide in water; by oxidizing, red phosphorus with nitric acid, or yellow phosphorus under the surface of water by bromine or iodine; and also by decomposing a mineral phosphate with sulphuric acid.

All soluble orthophosphates give with silver nitrate a characteristic yellow precipitate of silver phosphate, Ag 3 PO 4, soluble in ammonia and in nitric acid.

Its administration causes the appearance in the urine of a salt of cubebic acid which is precipitated by heat or nitric acid, and is therefore liable to be mistaken for albumin, when these two most common tests for the occurrence of albuminuria are applied.

It is insoluble in water; slightly soluble in solutions of carbonic acid and common salt, and readily soluble in concentrated hydrochloric and nitric acid.

Of the acid orthophosphates, the mono-calcium salt, CaH4(P04)2, may be obtained as crystalline scales, containing one molecule of water, by evaporating a solution of the normal salt in hydrochloric or nitric acid.

Sulphuric acid gives a white precipitate of calcium sulphate with strong solutions; ammonium oxalate gives calcium oxalate, practically insoluble in water and dilute acetic acid, but readily soluble in nitric or hydrochloric acid.

Ammonium nitrate, NH 4 NO 3, is prepared by neutralizing nitric acid with ammonia, or ammonium carbonate, or by double decomposition between potassium nitrate and ammonium sulphate.

Acids yield a sodium salt and free oxygen or hydrogen peroxide; with carbon dioxide it gives sodium carbonate and free oxygen; carbon monoxide gives the carbonate; whilst nitrous and nitric oxides give the nitrate.

Hot concentrated nitric acid oxidizes it to picric acid and oxalic acid, whilst on treatment with hydrochloric acid and potassium chlorate it yields chloranil (tetrachloroquinone).

In 1780 he proved that the acidity of sour milk is due to what was afterwards called lactic acid; and by boiling milk sugar with nitric acid he obtained mucic acid.

Nitric acid oxidizes it to benzoic acid and acetic acid.

It is completely oxidized to iodic acid when boiled with fuming nitric acid.

The soluble iodides, on the addition of silver nitrate to their nitric acid solution, give a yellow precipitate of silver iodide, which is insoluble in ammonia solution.

Iodic Acid, H10 3, can be prepared by dissolving iodine pentoxide in water; by boiling iodine with fuming nitric acid, 61+10HN03= 6H10 3 +10N0+2H 2 O; by decomposing barium iodate with the calculated quantity of sulphuric acid, previously diluted with water, or by suspending iodine in water and passing in chlorine, 12+5C12+ 6H 2 0=2H10 3 +10HC1.

It is prepared by oxidizing potassium ferrocyanide with a diluted nitric acid.

The free acid, when heated with concentrated sulphuric acid, is decomposed into water and pure carbon monoxide; when heated with nitric acid, it is oxidized first to oxalic acid and finally to carbon dioxide.

Wohler reduced the sesquioxide by zinc, and obtained a shining green powder of specific gravity 6.81, which tarnished in air and dissolved in hydrochloric acid and warm dilute sulphuric acid, but was unacted upon by concentrated nitric acid.

Chromium trioxide, Cr03, is obtained by adding concentrated sulphuric acid to a cold saturated solution of potassium bichromate, when it separates in long red needles; the mother liquor is drained off and the crystals are washed with concentrated nitric acid, the excess of which is removed by means of a current of dry air.

The nitrate, Cr(NO 3) 3.9H 2 0, crystallizes in purple prisms and results on dissolving the hydroxide in nitric acid, its solution turns green on boiling.

Again, silk dissolves freely in common nitric acid, which is not the case with wool.

The spectrum of nitrobenzene is also worth comparing with benzene and nitric acid.

Potash fusion converts it into acetic acid; nitric acid oxidizes it to acetic and oxalic acids; chromic acid mixture to acetaldehyde and acetic acid, and potassium permanganate to a0-dioxybutyric acid.

Magnesium Nitrate, Mg(NO 3) 2.6H 2 O, is a colourless, deliquescent, crystalline solid obtained by dissolving magnesium or its carbonate in nitric acid, and concentrating the solution.

Lacombe in 1904 obtained the pure salts by fractional crystallization of the nitric acid solution with magnesium nitrate in the presence of bismuth nitrate.

Thus he clearly described the preparation of hydrochloric acid by the action of oil of vitriol on common salt, the manifold virtues of sodium sulphate - sal mirabile, Glauber's salt - formed in the process being one of the chief themes of his Miraculum mundi; and he noticed that nitric acid was formed when nitre was substituted for the common salt.

Since the time of Henry Cavendish no one seemed even to have asked the question whether the residue was, in truth, all capable of conversion into nitric acid.

The temperature of the condenser is so regulated as to bring about the condensation of the nitric acid only, which runs out at the bottom of the pipe, whilst any uncondensed steam, nitrogen peroxide and other impurities pass into a Lunge tower, where they meet a descending stream of water and are condensed, giving rise to an impure acid.

For the production of nitric acid from air see Nitrogen.

Fuming nitric acid consists of a solution of nitrogen peroxide in concentrated nitric acid and is prepared by distilling dry sodium nitrate with concentrated sulphuric acid.

On mixing nitric acid with water there is a rise of temperature and a contraction in volume.

Iron when brought into contact with nitric acid under certain conditions, remains passive to the acid.

Nitric acid is without action on gold, platinum, iridium and rhodium.

The salts of nitric acid, known as nitrates, are mostly readily soluble in water and crystallize well.

They may be recognized by the fact that on the addition of a solution of ferrous sulphate, followed by that of concentrated sulphuric acid (the mixture being kept quite cold), the ferrous sulphate solution becomes of a deep brown colour, owing to the reducing action of the ferrous sulphate on the nitric acid which is liberated by the action of the sulphuric acid on the nitrate.

Nitric acid finds extensive application in the manufacture of sulphuric acid, certain coal-tar colouring matters, explosives, and in the production of various nitrates.

In medicine, nitric acid is used externally in a pure state as a caustic to destroy chancres, warts and phagadenic ulcers; and diluted preparations are employed in the treatment of dyspepsia, &c. Poisoning by strong nitric acid produces a widespread gastroenteritis, burning pain in the oesophagus and abdomen and bloody diarrhoea.

Other subjects on which he published papers were the inflammation of turpentine and other essential oils by nitric acid, and the methods of embalmment practised by the Egyptians.

The nitrate, Al(N03)3, is obtained as deliquescent crystals (with 81120) by evaporating a solution of the hydroxide in nitric acid.

Dilute nitric acid oxidizes it to acetic and oxalic acids, while potassium permanganate oxidizes it to acetone, carbon dioxide and oxalic acid.

Nitric acid converts it into nitro-compounds, which are occasionally used for dyeing silk and wool.

Martius yellow, C10H5(N02)20Na H20, the sodium salt of 2.4 dinitro-a-naphthol (for notation see Naphthalene), is prepared by the action of nitric acid on a-naphthol -2.4-disulphonic acid.

Naphthol yellow S., C10H4(ONa) (NO 2) 2 S0 3 Na, prepared by the action of nitric acid on a-naphthol - 2.4.

Bamberger (Ber., 18 94, 27, p. 9 1 4) obtained the diazoic acids, R NH NO 2, substances which he had previously prepared by similarly oxidizing the diazonium salts, by dehydrating the nitrates of primary amines with acetic anhydride, and by the action of nitric anhydride on the primary amines.

With concentrated sulphuric acid, fuming nitric acid,.

It burns in air, and also in chlorine and bromine, and is readily oxidized by nitric acid.

Lanthanum nitrate, La(N03)3 6H 2 0, is obtained by dissolving the oxide in nitric acid.

Potassium permanganate oxidizes it to f3-oxyisovaleric acid (CH 3) 2 C(OH) CH2.002H, whilst nitric acid gives, among other products, dinitropropane, (CH3)2C(N02)2.

In a fine state of division it takes fire on heating in air, but is permanent at ordinary temperatures in oxygen or air; it is readily attacked by hydrochloric and sulphuric acids, but scarcely acted on by nitric acid.

In organic chemistry he published papers on the decomposition of ammonium oxalate, with formation of oxamic acid, on amyl alcohol, on the cyanides, and on the difference in constitution between nitric and sulphuric ether.

C(OH) 000H, whilst concentrated nitric acid converts it into dinitroisopropane.

Besides having a considerable share in the commerce of the port of New York, Bayonne is an important manufacturing centre; among its manufactures are refined petroleum, refined copper and nickel (not from the ore), refined borax, foundry and machine-shop products, tubular boilers, electric launches and electric motors, chemicals (including ammonia and sulphuric and nitric acids), iron and brass products, wire cables and silk goods.

It is readily soluble in nitric and sulphuric acids, but less so in hydrochloric.

Thallous nitrate, T1NO 31 is obtained as white, rhombic prisms by crystallizing a solution of the metal, oxide, carbonate, &c., in nitric acid.

The chlorine is not completely precipitated by silver nitrate in nitric acid solution, the ionization apparently not proceeding to all the chlorine atoms. Thallic iodide, T11 3, is interesting on account of its isomorphism with rubidium and caesium tri-iodides, a resemblance which suggests the formula T11 (12) for the salt, in which the metal is obviously monovalent.

Urea may be recognized by its crystalline oxalate and nitrate, which are produced on adding oxalic and nitric acids to concentrated solutions of the base; by the white precipitate formed on adding mercuric nitrate to the neutral aqueous solutions of urea; and by the so-called "biuret" reaction.

In this process phosphates must be absent, and the nitric acid liberated during the reaction should be neutralized as soon as possible.

Riegler (ibid., 18 94, 33, p. 49) decomposes urea solutions by means of mercury dissolved in nitric acid, and measures the evolved gas.

It yields a nitroso derivative, is nitrated by nitric acid to dilituric acid and brominated by bromine.

With nitric acid in the presence of sulphuric acid it yields a nitro derivative.

Oxygen may be prepared by heating mercuric oxide; by strongly heating manganese dioxide and many other peroxides; by heating the oxides of precious metals; and by heating many oxy-acids and oxy-salts to high temperatures, for example, nitric acid, sulphuric acid, nitre, lead nitrate, zinc sulphate, potassium chlorate, &c. Potassium chlorate is generally used and the reaction is accelerated and carried out at a lower temperature by previously mixing the salt with about one-third of its weight of manganese dioxide, which acts as a catalytic agent.

The pure metal readily evolves hydrogen when acted upon by sulphuric and hydrochloric acids, and is readily attacked by dilute nitric acid.

Cold concentrated nitric and sulphuric acids are without action on the metal, but it reacts rapidly with dilute nitric and hydrochloric acids.

By suspending the precipitated cerous hydroxide in water and passing chlorine through the solution, a hydrated form of the dioxide, 2CeO 2.3H 2 O, is obtained, which is readily soluble in nitric and sulphuric acids, forming ceric salts, and in hydrochloric acid, where it forms cerous chloride, with liberation of chlorine.

Nitric acid and chromic acid oxidize them in such a manner that they yield the same products as the alcohols from which they are derived.

Gallium oxide Ga203 is obtained when the nitrate is heated, or by solution of the metal in nitric acid and ignition of the nitrate.

Meta-dinitrobenzene is formed by the direct nitration of nitrobenzene with fuming nitric acid, the product being poured into water and recrystallized from dilute alcohol.

It exists in two crystalline forms. Nitric acid passed into its chloroform solution gives phenyl diazonium nitrate.

Fuming nitric acid gives a paratrinitro substitution derivative which on reduction gives paraleucaniline; the salt of the carbinol formed on oxidizing this substance is the valuable dye rosaniline.

It is very heavy, its density being about 11; it inflames when heated in air and is not attacked by alkalis; it readily dissolves in nitric acid and aqua regia, but with difficulty in hydrochloric acid.

St Edme (Comptes rendus, 1886, 106, p. 1079) sheet nickel is passive to nitric acid, and the metal remains passive even when heated to redness in a current of hydrogen.

Hydrochloric and sulphuric acids are almost without action on the metal, but it dissolves readily in dilute nitric acid.

Rubidium nitrate, RbNO 3, obtained by the action of nitric acid on the carbonate, crystallizes in needles or prisms and when strongly heated is transformed into a mixture of nitrite and oxide.

Chalcopyrite is decomposed by nitric acid with separation of sulphur and formation of a green solution; ammonia added in excess to this solution changes the green colour to deep blue and precipitates red ferric hydroxide.

It is soluble in a mixture of nitric and hydrofluoric acids, and the powdered metal, in aqua regia, but slowly attacked by sulphuric, hydrochloric and hydrofluoric acids separately; it is also soluble in boiling potash solution, giving a tunstate and hydrogen.

A nitride, W2N3, is obtained as a black powder by acting with ammonia on the oxytetrachloride or hexachloride; it is insoluble in sodium hydroxide, nitric and dilute sulphuric acids; strong sulphuric acid, however, gives ammonia and tungstic acids.

For this purpose a filtered solution of bleaching-powder and a very dilute solution of nitric acid may be employed.

By boiling this varnish with dilute nitric acid vapours of acrolein are given off, and the substance gradually becomes a solid non-adhesive mass the same as the ultimate oxidation product of both raw and boiled oil.

It may be prepared by the oxidation of fats and of fatty acids by nitric acid, and is also a product of the fermentation of malic and tartaric acids.

In another experiment he fired, by the electric spark, a mixture of hydrogen and oxygen (dephlogisticated air), and found that the resulting water contained nitric acid, which he argued must be due to the nitrogen present as an impurity in the oxygen ("phlogisticated air with which it [the dephlogisticated air] is debased").

In the 1785 paper he proved the correctness of this supposition by showing that when electric sparks are passed through common air there is a shrinkage of volume owing to the nitrogen uniting with the oxygen to form nitric acid.

Further, remarking that little was known of the phlogisticated part of our atmosphere, and thinking it might fairly be doubted "whether there are not in reality many different substances confounded together by us under the name of phlogisticated air," he made an experiment to determine whether the whole of a given portion of nitrogen (phlogisticated air) of the atmosphere could be reduced to nitric acid.

Concentrated nitric acid has also very little action, but with the dilute acid a vigorous action ensues.

The first products of this reaction are copper nitrate and nitric oxide, but, as the concentration of the copper nitrate increases, nitrous oxide and, eventually, free nitrogen are liberated.

It may be prepared by heating cuprous sulphide with sulphur, or triturating cuprous sulphide with cold strong nitric acid, or as a dark brown precipitate by treating a copper solution with sulphuretted hydrogen.

It decomposes when heated to 900; with water it gives nitric oxide and cupric nitrate and nitrite.

Cupric nitrate, Cu(NO 3) 2, is obtained by dissolving the metal or oxide in nitric acid.

Cooh, is obtained by the oxidation of milk, sugar, dulcite, galactose, quercite and most varieties of gum by nitric acid.

Barium nitrate, Ba(N03)2, is prepared by dissolving either the carbonate or sulphide in dilute nitric acid, or by mixing hot saturated solutions of barium chloride and sodium nitrate.

Nitric acid oxidizes antimony either to the trioxide Sb 4 0 6 or the pentoxide Sb 2 0 5, the product obtained depending on the temperature and concentration of the acid.

Antimony trioxide occurs as the minerals valentinite and senarmontite, and can be artificially prepared by burning antimony in air; by heating the metal in steam to a bright red heat; by oxidizing melted antimony with litharge; by decomposing antimony trichloride with an aqueous solution of sodium carbonate, or by the action of dilute nitric acid on the metal.

It is a white powder, almost insoluble in water, and when volatilized, condenses in two crystalline forms, either octahedral or prismatic. It is insoluble in sulphuric and nitric acids, but is readily soluble in hydrochloric and tartaric acids and in solutions of the caustic alkalies.

It is a white powder almost insoluble in water and nitric acid, and when heated, is first converted into metantimonic acid, HSbO 3, and then into the pentoxide Sb205.

When the latter have oxidized ammonia to nitrite, however, the former step in and oxidize it still further to nitric acid.

In addition to the bacterial actions which result in the oxidization of ammonia to nitrous acid, and of the latter to nitric acid, the reversal of such processes is also brought about by numerous bacteria in the soil, rivers, &c. Warington showed some time ago that many species are able to reduce nitrates to nitrites, and such reduction is now known to occur very widely in nature.

With concentrated nitric acid, in the presence of cold concentrated sulphuric acid, it yields trinitro-resorcin (styphnic acid), which forms yellow crystals, exploding violently on rapid heating.

In ores containing much copper, this metal is largely concentrated in the lead button, making it hard, and necessitating repeated scorifications and, in some cases, a preliminary removal of the copper by solution of the ore in nitric acid.

If the lead is therefore rightly proportioned to the standard of alloy, the resulting button will consist of only gold and silver, and these are separated by the operation of parting, which consists in boiling the alloy (after rolling it to a thin plate) in strong nitric acid, which dissolves the silver and leaves the gold as a coherent sponge.

Nearly all lead ores contain more or less sulphur; and as in the process of solution in nitric acid this is oxidized to sulphuric acid which unites with the lead to form the very insoluble lead sulphate, it is simpler to add sulphuric acid to convert all the lead into sulphate and then evaporate until the nitric acid is expelled.

The ore (0 5 gramme) is digested with a mixture of potassium nitrate and nitric acid.

A saturated solution of potassium chlorate in strong nitric acid is added, and the mass evaporated to dryness.

This method is modified in practice by the character of the ores, carbonates and silicates free from sulphides being decomposed by hydrochloric acid, with the addition of a little nitric acid.

In the electrolytic method from o 5 to 5 grammes of ore are treated in a flask or beaker, with a mixture of io cc. of nitric and ro cc. of sulphuric acid, until thoroughly decomposed.

One gramme of the ore is treated in a flask with a mixture of nitric and sulphuric acids and evaporated until all the nitric acid is expelled.

The copper is then dissolved in 5 cc. of nitric acid; if silver is present a drop or two of hydrochloric acid is added, the solution diluted to about 50 cc., and filtered.

To the filtrate (or, if no silver is present, to the diluted nitric acid solution) io cc. of ammonia are added, and a standard solution of potassium cyanide is run in from a burette until the blue colour has nearly disappeared.

The potassium cyanide solution is standardized by dissolving 0.5 gramme o£ pure copper in 5 cc. of nitric acid, diluting, adding io cc. of ammonia, and titrating exactly as described above.

The ore is treated as described in the cyanide method until the copper precipitated by the aluminium foil has been washed and dissolved in 5 cc. of nitric acid; then 0.25 gramme of potassium chlorate is added, and the solution boiled nearly dry to oxidize any arsenic present to arsenic acid.

A few drops of starch solution are then added, and when the blue colour has nearly vanished a drop or two of methyl orange makes the end reaction very sharp. The thiosulphate solution is standardized by dissolving o 3 to o 5 gramme of pure copper in 3 cc. of nitric acid, adding 50 cc. of water and 5 cc. of ammonia, and titrating as above after the addition of 5 cc. of glacial acetic acid and 5 cc. of the potassium iodide solution.

It is readily soluble in dilute nitric acid, nitric oxide and silver nitrate being formed; it also dissolves in hot, strong sulphuric acid, sulphur dioxide being evolved.

It is almost insoluble in water, soluble in 50,000 parts of nitric acid, and more soluble in strong hydrochloric acid and solutions of alkaline chlorides.

It is very slightly soluble in nitric acid, and less soluble in ammonia than the chloride.

Silver nitrate, AgNO 3, one of the most important silver salts, is obtained by dissolving the metal in moderately dilute nitric acid; on evaporation it separates in the anhydrous form as colourless triclinic plates.

It is a very stable compound, chromic and nitric acids being without action upon it, whilst the halogens only yield substitution derivatives with difficulty.

In this process, the residues are boiled with a dilute sulphuric acid to which nitric acid and potassium chlorate are added in order to transform the element into selenic acid, H 2 Se0 4, which is then reduced to selenious acid, H 2 Se0 3, by boiling with hydrochloric acid, and finally to selenium by sulphur dioxide.

Selenium dioxide, Se02, is prepared by burning selenium in oxygen, or by oxidizing selenium with nitric acid and heating the residue.

Silver nitrate in the presence of nitric acid gives with bromides a pale yellow precipitate of silver bromide, AgBr, which is sparingly soluble in ammonia.

For their quantitative determination they are precipitated in nitric acid solution by means of silver nitrate, and the silver bromide well washed, dried and weighed.

Chromic acid oxidizes it to acetic acid and carbon dioxide; potassium permanganate oxidizes it to pyruvic acid; nitric acid to oxalic acid, and a mixture of manganese dioxide and sulphuric acid to acetaldehyde and carbon dioxide.

Scheele treated bone ash with nitric acid, precipitated the calcium as sulphate, filtered, evaporated and distilled the residue with charcoal.

Hittorf's phosphorus is another crystalline allotrope formed by heating phosphorus with lead in a sealed tube to redness, and removing the lead by boiling the product with nitric and hydrochloric acid.

On oxidation with nitric acid the primary compounds give monoalkyl phosphinic acids, R PO(OH) 2r the secondary yielding dialkyl phosphinic acids, R 2 PO(OH).

Dilute nitric acid oxidizes it first to para-toluic acid and then to terephthalic acid.

Cinchoninic acid (quinoline-y-carboxylic acid) is formed when cinchonine is oxidized by nitric acid, or by the oxidation of lepidine.

Hydrochloric, hydrobromic, hydriodic, hydrofluoric, nitric, phosphoric and many other acids are manufactured by the action of sulphuric acid on their salts; the alkali and chlorine industries, and also the manufacture of bromine and iodine, employ immense quantities of this acid.

As this reaction of its own accord takes place only to a very small extent, an" oxygen carrier "is always introduced in the shape of the vapours of nitric acid or the lower oxides of nitrogen.

The commercial production of sulphuric acid imperatively requires that the nitrogen oxides (which originally were always introduced in the shape of nitric acid) should be available as long as possible, before being lost mechanically or by reduction to the inactive forms of nitrous oxide or elementary nitrogen.

The supply of the nitric acid required to make up this loss is obtained in England by "potting" that is, by decomposing solid nitrate of soda by sulphuric acid in a flue between the pyrites burners and the chambers.

On the continent of Europe makers generally prefer to employ liquid nitric acid, which is run through the Glover tower together with the nitrous vitriol.

It is difficult, however, to limit its action, and glacial acetic and nitric acids are preferable for this purpose.

Nitric acid oxidizes it to adipic acid, and chromic acid to cyclo-hexanone.

The formation of murexide is used as a test for the presence of uric acid, which on evaporation with dilute nitric acid gives alloxantin, and by the addition of ammonia to the residue the purple red colour of murexide becomes apparent.

It dissolves in dilute cold nitric acid with the formation of ferrous and ammonium nitrates, no gases being liberated; when heated or with stronger acid ferric nitrate is formed with evolution of nitrogen oxides.

Pyrite may be prepared artificially by gently heating ferrous sulphide with sulphur, or as brassy octahedra and cubes by slowly heating an intimate mixture of ferric oxide, sulphur and salammoniac. It is insoluble in dilute acids, but dissolves in nitric acid with separation of sulphur.

The solution absorbs nitric oxide to form a dark brown solution, which loses the gas on heating or by placing in a vacuum.

Ferric sulphate, Fe2(S04)3, is obtained by adding nitric acid to a hot solution of ferrous sulphate containing sulphuric acid, colourless crystals being deposited on evaporating the solution.

Ferric nitrate, Fe(NO3) 3, is obtained by dissolving iron in nitric acid (the cold dilute acid leads to the formation of ferrous and ammonium nitrates) and crystallizing, when cubes of Fe(NO3)3.6H20 or monoclinic crystals of Fe(N03)3.9H20 are obtained.

Ferrous solutions absorb nitric oxide, forming dark green to black solutions.

The coloration is due to the production of unstable compounds of the ferrous salt and nitric oxide, and it seems that in neutral solutions the compound is made up of one molecule of salt to one of gas; the reaction, however, is reversible, the composition varying with temperature, concentration and nature of the salt.

The heptanitroso acid is precipitated as a brown amorphous mass by dilute sulphuric acid, but if the salt be heated with strong acid it yields nitrogen, nitric oxide, sulphur, sulphuretted hydrogen, and ferric, ammonium and potassium sulphates.

On reduction it yields hexahydrotoluene; oxidation with dilute nitric acid or chromic acid gives benzoic acid; whilst chromyl chloride and water give benzaldehyde.

A typical member is nitric oxide; carbon monoxide and nitrous oxide may also be put in this class, but it must be remembered that these oxides may be regarded, in some measure at least, as the anhydrides of formic and hyponitrous acid, although, at the same time, it is impossible to obtain these acids by simple hydration of these oxides.

It dissolves slowly in hydrofluoric acid and in nitric acid, the solution turning blue; it is insoluble in hydrochloric acid.

Pyrovanadic acid is deposited as a dark brown unstable powder when an acid vanadate is decomposed by nitric acid.

It is easily oxidized by heating with concentrated nitric acid to arsenic acid, and with concentrated sulphuric acid to arsenic trioxide; dilute nitric acid only oxidizes it to arsenious acid.

A blank experiment should always be carried out in testing for small quantities of arsenic, to ensure that the materials used are quite free from traces of arsenic. It is to be noted that the presence of nitric acid interferes with the Marsh test; and also that if the arsenic is present as an arsenic compound it must be reduced to the arsenious condition by the action of sulphurous acid.

For the pyroarsenate method it is necessary that the arsenic should be in the arsenic condition, if necessary this can be effected by heating with nitric acid; the acid solution is then mixed with "magnesia mixture" and made strongly alkaline by the addition of ammonia.

It is then allowed to stand twenty-four hours, filtered, washed with dilute ammonia, dried, ignited to constant weight and weighed, the filter paper being incinerated separately after moistening with nitric acid.

The prismatic variety of the oxide can be obtained by crystallization from a saturated boiling solution in potassium hydroxide, or by the crystallization of a solution of silver arsenite in nitric acid.

By the action of oxidizing agents such as nitric acid, iodine solution, &c., arsenious acid is readily converted into arsenic acid, in the latter case the reaction proceeding according to the equation H3AsO3 +I2 + H2O = H3AsO4 + 2HI.

Arsenic pentoxide, As2O5, is most easily obtained by oxidation of a solution of arsenious acid with nitric acid; the solution on concentration deposits the compound 2H3AsO4.

On oxidation by nitric acid they yield sulphonic acids.

Acids, other than carbonic, may promote rusting; this is particularly the case with ironwork exposed to the acids - sulphurous, nitric, &c. - contained in smoke.

The trichromates are obtained by the addition of nitric acid (of specific gravity about 1.2) to solutions of the bichromates.

It is also obtained when sebacic, stearic and oleic acids are oxidized with nitric acid.

They yield mucic and oxalic acids when treated with nitric acid.

Sulphuric acid converts it into l-arabinose; and nitric acid oxidizes it to oxalic acid (without the intermediate formation of mucic acid as in the case of gum arable).

Linseed does not give the latter reaction; by treatment with boiling nitric acid it yields mucic and oxalic acids.

During this manual operation the dosage program for nitric acid was unintentionally activated for a second time.

Defects in platelet adhesion may also be related to excessive nitric oxide (NO) production.

Recent research has shown that dilation of the blood vessels in the brain relates to nitric oxide.

It has been well established that nitric oxide donors such as glyceryl trinitrate (GTN) can induce a reversible chemical sphincterotomy.

Vascular integrity in the healthy endothelium is maintained through the release of a variety of paracrine factors such as nitric oxide (NO ).

Inhaled nitric oxide in full-term and nearly full-term infants with hypoxic respiratory failure.

It transforms in the air to form gaseous nitric acid and toxic organic nitrates.

Further it will eventually breakdown to produce nitric acid and hence give rise to acid rain which harms the environment.

Reprocessing involves the dissolution of the spent fuel in boiling concentrated nitric acid and subsequent physico-chemical separations of uranium and plutonium.

We are examining the role of the free radical, nitric oxide (NO ), in this process.

Recent data has revealed that stretch injury may enhance contractility but also increase the sensitivity of the vessel to agents which release nitric oxide.

In particular, they appear to enhance the production of a hormone-like substance called nitric oxide from the inside wall of arteries.

Smog forming emissions are generally 30-50% lower including nitric oxides and hydrocarbons emissions.

We showed that nitric oxide did not play a role in normal or abnormal pregnancy and speculated that other vasodilators may be involved.

Kendrick KM et al (1997) Formation of olfactory memories mediated by nitric oxide.

Nitric oxide (NO) the main constituent of these emissions, reacts to form nitrogen dioxide (NO2 ).

The dissolver, full of intensely radioactive nitric acid, is behind extremely thick shielding.

In addition, the cleavage of arginine by nitric oxide synthetase generates citrulline, which is a urea cycle intermediate.

It is the finer Type I PSC's consisting of nitric acid trihydrate which give the spectacular colorful displays.

In this process the osmiridium is fused with zinc and the excess of zinc evaporated; the residue is then ignited with barium nitrate, extracted with water and boiled with nitric acid.

The double chloride is fused with nitre, the melt extracted with water and the residue fused with lead, the excess of lead being finally removed by solution in nitric acid and aqua regia.

Thus 5 parts by weight of soda, 7 of potash and 3.5 of quicklime will each neutralize 4.56 parts of hydrochloric acid or 7.875 of nitric or 6.125 parts of sulphuric acid; these weights, in fact, are mutually equivalent to one another.

Berglund (Berichte, 18 74, 7, p. 469), in aqueous solution, by dissolving ammonium cobaltocobaltisulphite (NH4)2C02 [(S03) 6 'C02] 14H 2 O in dilute hydrochloric or nitric acids, or by decomposition of its silver salt with hydrochloric acid.

Cobalt nitrate, Co(NO 3) 2.6H 2 0, is obtained in dark-red monoclinic tables by the slow evaporation of a solution of the metal, its hydroxide or carbonate, in nitric acid.

From its aqueous solution, concentrated hydrochloric acid precipitates hydrocobalticyanic acid, H 3 Co(CN) 61 as a colourless solid which is very deliquescent, and is not attacked by concentrated hydrochloric and nitric acids.

Jowitschitsch (Ann., 1906, 347, p. 2 33) inclines to Scholl's formula; he found that the synthetic silver salt of glyoxime peroxide resembled silver fulminate in yielding hydroxylamine with hydrochloric acid, but differed in being less explosive, and in being soluble in nitric acid.

By nitrating phenol with concentrated nitric acid, no care being taken to keep the temperature of reaction down, trinitrophenol (picric acid) is obtained (see Picric Acid).

Thus, it must be supposed that in nitric oxide, NO, an odd number of affinities are disengaged, since a single atom of dyad oxygen is united with a single atom of nitrogen, which in all its compounds with other elements acts either as a triad or pentad.

The synthesis of nitric acid by passing electric sparks through moist air by Cavendish is a famous piece of experimental work, for in the first place it determined the composition of this important substance, and in the second place the minute residue of air which would not combine, although ignored for about a century, was subsequently examined by Lord Rayleigh and Sir William Ramsay, who showed that it consists of a mixture of elementary substances - argon, krypton, neon and xenon (see Argon).

Nitric acid (up to 50%) is formed in the first tower, and weaker acids in the successive ones; the last tower contains milk of lime which combines with the gases to form calcium nitrite and nitrate (this product, being unsuitable as a manure, is decomposed with the acid, and the evolved gases sent back).

This method does not give a pure gas, varying amounts of nitrous oxide and nitrogen being present (see Nitric Acid).

In 1849 he discovered anhydrous nitric acid (nitrogen pentoxide), a substance interesting as the first obtained of the so-called " anhydrides " of the monobasic acids.

In some cases, especially in dry distillations, the furnace flames play directly on the retorts, in others, such as in the case of nitric acid, the whole still comes under the action of the furnace gases to prevent condensation on the upper part of the still, while in others the furnace gases do not play directly on the base or upper portion of the still but are conducted around it by a system of flues (see Coal-Tar).

The salts of bismuth are feebly antiseptic. Taken internally the subnitrate, coming into contact with water, tends to decompose, gradually liberating nitric acid, one of the most powerful antiseptics.

The amount of nitric acid varies from place to place; rain-water, collected in the country, has been found to contain an average of o 5 parts in a million, but town rain-water contains more, the greater amounts being present in the more densely populated districts.

Baumann, Ber., 1885, 18, p. 883), and with concentrated nitric acid they yield dinitroparaffins (G.

Fischer, Ann., 1882, 215, p. 283), or from glycerin diacetate and concentrated nitric acid in the cold (E.

Trinitrobenzenes, C 6 H 3(N02)3.-Asymmetrical (1.2.4) trinitrobenzene results from the action of fuming nitric and sulphuric acids on para-dinitrobenzene.

Hydrochloric acid and its metallic salts can be recognized by the formation of insoluble silver chloride, on adding silver nitrate to their nitric acid solution, and also by the formation of chromium oxychloride (see above).