Ferric potassium chromate

Ferric ammonium chromate, (NH4)2Cr04.Fe2(Cr04)3.4H20, and ferric potassium chromate, K2Cr04.Fe2(Cr04)3.4H20, have been prepared 2 as dark red crystalline plates by the slow evaporation of mixed solutions of ferric chloride and ammonium (or potassium) dichromate. 

DeNOx (1) A Denox process for removing nitrogen oxides from the gaseous effluents from nitric acid plants. The oxides are reduced with ammonia, over a catalyst containing potassium chromate and ferric oxide. Developed by Didier Werke in the 1980s. 

Synonym Neatsfoot Oil Necatorina Nechexane Neutral Ahhonium Pluoride Neutral Anhydrous Calcium Hypochlorite Neutral Lead Acetate Neutral Nicotine Sulfate Neutral Potassium Chromate Neutral Sodium Chromatetanhydrous Neutral Verdigris Nickel Acetate Nickel Acetate Tetrahyorate Nickel Ammonium Sulfate Nickel Ammonium Sulfate Hexahydrate Nickel Bromide Nickel Bromide Trihydrate Nickel Carbonyl Nickel Chloride Nickel Chloride Nickel Cyanide Nickel Iiu Fluoborate Nickel Fluoroborate Solution Nickel Fluoroborate Nickel Formate Nickel Formate Dihyorate Nickel Nitrate Nickel Nitrate Hexahydrate Nickel Sulfate Nickel Tetracarbokyl Nickelous Acetate Nickelous Sulfate Nicotine Nicotine Sulfate Nifos Nitralin Nitram O-Nitraniline P-Nitraniline Nitric Acid Nitric Acid, Aluminum Salt Nitric Acid, Iron (111) Salt Compound Name Oil Neatsfoot Carbon Tetrachloride Neohexane Ammonium Fluoride Calcium Hypochlorite Lead Acetate Nicotine Sulfate Potassium Chromate Sodium Chromate Copper Acetate Nickel Acetate Nickel Acetate Nickel Ammonium Sulfate Nickel Ammonium Sulfate Nickel Bromide Nickel Bromide Nickel Carbonyl Nickel Chloride Nickel Chloride Nickel Cyanide Nickel Fluoroborate Nickel Fluoroborate Nickel Fluoroborate Nickel Formate Nickel Formate Nickel Nitrate Nickel Nitrate Nickel Sulfate Nickel Carbonyl Nickel Acetate Nickel Sulfate Nicotine Nicotine Sulfate Tetraethyl Pyrophosphate Nitralin Ammonium Nitrate 2-Nitroaniline 4-Nitroaniline Nitric Acid Aluminum Nitrate Ferric Nitrate... 

Chlorides, bromides, and iodides can be quantitatively determined by treatment with silver nitrate, and, with suitable precautions, the precipitated halide is washed, dried, and weighed. Chlorides in neutral soln. can be determined by F. Mohr s volumetric process 27 by titration with a standard soln. of silver nitrate with a little potassium chromate or sodium phosphate as indicator. When all the chloride has reacted with the silver nitrate, any further addition of this salt gives a yellow coloration with the phosphate, and a red coloration with the chromate. In J. Volhard s volumetric process, the chloride is treated with an excess of an acidified soln. of silver nitrate of known concentration. The excess of silver nitrate is filtered from the precipitated chloride, and titrated with a standard soln. of ammonium thiocyanate, NH4CN8—a little ferric alum is used as indicator. When the silver nitrate is all converted into thiocyanate AgN03-fNH4CNS=AgCNS +NH4NOS, the blood-red coloration of ferric thiocyanate appears. 

The hydrazines usually are converted to hydrocarbons by treatment with hot, aqueous cupric sulfate, ferric chloride, or potassium chromate.7- uo 1Ui 116 113 Although hydrazines often are isolated from reduction mixtures as hydrochlorides, it is advisable to convert them to the free bases before carrying out the oxidation if this is not done, a chlorine atom may replace the hydrazine group.117 118< 119 Phenylhydrazine hydrochloride is converted to chlorobenzene in 86% yield when treated with a solution of cupric sulfate containing hydrochloric add.118... 

Volumetric estimation4 in neutral solution can be effected by titration with standard sodium chloride, potassium chromate being employed as indicator and in nitric-acid solution with thiocyanate, using ferric alum as indicator, or with sodium chloride without any external indicator. 

In a back-titration of silver by chloride ions, potassium chromate can be used to indicate the endpoint (Mohr s method) but with potassium thiocyanate as tifrant, anunonium iron(III) sulfate ( ferric alum ) is preferred. In the direct titration (Gay-Lussac s method) the location of the turbidimetric endpoint has been improved in detail. ... 

A mixture of powdered chromite ore and potassium carbonate slowly forms potassium chromate, KoCr04, when strongly heated in air. The oxygen of the air oxidizes chromium to the sexipositive state, and also oxidizes the iron to ferric oxide ... 

Ferric Chromate has not been obtained as the normal salt, but by digesting ferric hydroxide with chromic acid, a brown amorphous substance, soluble in water and alcohol, and of composition FcjOj.-tCrOa, has been obtained. By the addition of potassium chromate to a solution of a ferric salt, a brown precipitate, of composition FcgOa.CrOg, is obtained. It is decomposed by water. 

L. Passerini, and V. M. Goldschmidt and co-workers studied the solid soln. with alumina, and with ferric oxide q.v.). W. Muller said that the oxide prepared by reducing potassium chromate with dry—not moist—hydrogen chloride is quite different from the ordinary oxide, being greyish-green, composed of tube-like plates of the hardness of graphite. 

Ferric ferrocyanide Zinc potassium chromate pigment, zinc white Carbon monoxide pigment dispersant leather PEG-32 castor oil PEG-75 castor oil PEG-160 castor oil... 

Carey Lea failed to find any sensitising action of dyes on ferric oxalate, potassium chromate, uranyl nitrate, etc. The research of J. M. Eder was fundamental in the study of sensitisation by dyestuffs. J. J. Acworth found a rough correlation between the absorption maximum of a coloured silver bromide gelatin plate and the maximum of chemical activity in the region of the spectrum, although this was always displaced towards the violet. The development of this work into panchromatic plates is well known. 

Copper sulfate Ferric chloride 50% aq. sol n Ferrous chloride 50% aq. sol n Lithium chloride >30% aq. sol n Mercuric chloride sat d aq. sol n Potassium acetate sat d aq. sol n Potassium carbonate Potassium chromate sat d aq. sol n Potassium iodide... 

The most suitable oxidizing agent is potassium ferricyanide, but ferric chloride, hydrogen peroxide ia the presence of ferrous salts, ammonium persulfate, lead dioxide, lead tetraacetate or chromate, or silver and cupric salts may be useful. Water mixed, eg, with methanol, dimethylformamide, or glycol ethers, is employed as reaction medium. 

Another important factor is the thermal stability and heat of decomposition of the oxidizer. Potassium chlorate mixtures tend to be much more sensitive to ignition than potassium nitrate compositions, due to the exothermic nature of the decomposition of KCIO 3. Mixtures containing very stable oxidizers - such as ferric oxide (Fe 2O 3) and lead chromate (PbCrO 4) - can be quite difficult to ignite, and a more-sensitive composition frequently has to be used in conjunction with these materials to effect ignition. 

Occluded hydrogen is more reactive chemically than the normal gas. Hydrogenated palladium precipitates mercury and mercurous chloride from an aqueous solution of the dichloride, without any evolution of hydrogen. It reduces ferric salts to ferrous potassium ferricyanide to ferrocyanide chlorine water to hydrochloric add iodine water to hydriodic acid 2 chromates to chromic salts ceric to cerous salts whilst cupric, stannic, arsenic, manganic, vanadic, and molybdic compounds are also partially reduced.3... 

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