Lead Acetate Chromate

Dilead hexacyanokisferrate [14402-61 -0] Pb2[Fe(CN)g], is a white precipitate that forms when lead acetate is added to Ca2[Fe(CN)g]. It is insoluble in water or dilute acids but is soluble in hot ammonium chloride or ammonium succinate solutions. It has been used as a quaUtative analytical reagent in tests for cadmium and chromate. 

Lead chromates are prepared by precipitation techniques from soluble salts ia aqueous media. The raw material Hst iacludes a number of different lead compounds, eg, Htharge, lead nitrate, basic lead acetate, basic lead carbonate, as well as acids, alkahes, sodium bichromate, and sodium chromate. The typical reaction can be represented by the foUowiag equation ... 

Lead continues to be used in pigments. For example, lead chromate and lead oxide are used in paints, and lead acetate is used in hair dyes. 

Lead chromate is found naturally in minerals crocoite and phoenicochroite. It also is readily prepared by adding a soluble chromate such as sodium or potassium chromate to a solution of lead nitrate, lead acetate or other soluble lead(II) salt in neutral or slightly acidic solution ... 

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... 

Amm acetate soln and add sufficient Na bichromate soln to ppt all lead as chromate. Test for the completion of destruction by transferring a portion of slurry to a filter paper and treating the filtrate with a few drops of Na bichromate soln. Confirm the absence of LA by washing.with distd w,the residue on filter,free of so azide salts, drying it,and subjecting a 20 mg portion to the impact test, using 2 kg wt. The material should not detonate... 

Prepare about 30 g. of normal lead chromate, PbCr04 (Exercise 23), by the double decomposition of lead acetate and potassium dichromate and wash the precipitate until it is free from soluble lead salts. Suspend the yellow chromate in a dilute solution of sodium hydroxide (1 20) and boil until the color has changed to a bright brick red. This material is a basic chromate known as chrome red, having the composition represented by the formula PbCr04-PbO ... 

Lead acetate Yellow precipitate of lead chromate soluble in dilute nitric acid insoluble in acetic acid... 

Lead chromates and lead molybdates are produced by precipitation of soluble salts in aqueous media. Various lead sources include litharge, lead nitrate, basic lead actetate, and lead carbonate. The lead carbonate and basic lead acetate are used primarily to control particle size. Other ingredients include acids, alkalis, sodium bichromate, and sodium chromate. Additionally, molybdate orange manufacture involves the use of sodium molybdate and sodium sulfate as raw materials. 

Lead acetate solution white precipitate of lead sulphate, PbS04, soluble in hot concentrated sulphuric acid, in solutions of ammonium acetate and of ammonium tartrate (see under Lead, Section III.4, reaction 5), and in sodium hydroxide solution. In the last case sodium tetrahydroxoplumbate(II) is formed, and on acidification with hydrochloric acid, the lead crystallizes out as the chloride. If any of the aqueous solutions of the precipitate are acidified with acetic acid and potassium chromate solution added, yellow lead chromate is precipitated (see under Lead, Section III.4, reaction 6). 

Heat with sodium carbonate and potassium nitrate This test may be carried out in a loop of platinum wire or upon platinum foil or upon a piece of broken porcelain. If chromium is present, a yellow melt is produced. This should be dissolved in water, acidified with dilute acetic acid, and (a) silver nitrate solution added, when brownish-red silver chromate is precipitated, (6) lead acetate solution added, when yellow lead chromate is precipitated, or (c) 1-2 ml diphenylcarbazide reagent added, when a deep-red colouration is produced. 

Chromate, (i) Hydrogen peroxide test (IV.33, 4). (ii) Lead acetate solution test (IV.33,3). (iii) Action of hydrogen sulphide or sulphur dioxide (IV.33, 5,6). 

Precipitated lead chromate tends to change colour during filtration, becoming orange. This is due to the formation of the red basic salt, PbaCrOg or PbCr04.PbO, by hydrolysis, which is the more likely to take place when the salt is prepared from basic lead acetate. ... 

Double salts of lead chromate with alkali chromates have been obtained. The potassium salt, K3Cr04.PbCr04 or KaPb(Cr04)2, is formed as a yellow amorphous precipitate when SO c.c. of a saturated solution of potassium chromate is mixed with 10 c.c. of saturated lead acetate solution. The ammonium salt, (NH4)2Pb(Cr04)2, is prepared similarly, and both salts are decomposed into their components by %vater. 

Potassium chromate and lead(II) acetate are both dissolved in a beaker of water, where they react to form solid lead(II) chromate. What is the balanced net ionic equation describing this reaction ... 

Chromium. Mixed with sodium carbonate and potassium nitrate and fused in a platinum wire loop gives yellow potassium chromate. A solution of the bead in acetic acid, gives yellow precipitate with lead acetate. 

Chromates.—(1.) HaS in acid solution, brownish color, changing to green. (3.) Ammonium sulfhydrate, greenish ppt. (3.> Barium chlorid, yellowish ppt. (4.) Silver nitrate, brownish-red ppt., soluble in HNOsOr KHtHO. (5.) Lead acetate, yellow ppt.> soluble in potash, insoluble in acetic acid. 

F. H. Storer obtained chromyl chloride. H. Moissan, 0. Popp, etc., found that it is soluble in sulphuric acid. W. Manchot and R. Kraus found that when warmed with sulphur dioxide, sulphur trioxide is formed and warm sulphurous acid is converted into sulphuric acid. C. W. Eliot and F. H. Storer, 0. Popp, etc., observed that chromic dioxide readily dissolves in dU. nitric acid the soln. is reddish-brown, and gives a dirty green precipitate with ammonia. W. Manchot and R. Kraus found that cone, nitric acid converts the dioxide into chromic acid. E. Hintz found that it is scarcely attacked by phosphorus pentachloride at 250°. A. Maus stated that a little arsenic acid converts the dioxide into chromic arsenate, which is soluble in an excess of arsenic acid. The dioxide is insoluble in ether, acetone, and other organic liquids and 0. Popp said that the dioxide dissolves with difficulty in acetic acid. M. Kriiger, W. Manchot and R. Kraus, etc., observed that boiling potassium or sodium hydroxide converts the dioxide into a soln. of alkali chromate, and a precipitate of hydrated chromic oxide. This simultaneous oxidation and reduction furnishes an illustration of the acidic and basic properties of chromium dioxide. A. Maus found that when digested with lead acetate in... 

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