ISDUSTRI-4L d N D ENGINEERISG CHEMISTRY
May, 1927
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Recommended Specifications for Analytical Reagent Chemicals' Ammonium Nitrate, Ammonium Phosphate Dibasic (Diammonium Hydrogen Phosphate), Barium Carbonate, Barium Hydroxide [ Ba(OH)?.8Hz0], Cupric Sulfate, Lead Dioxide, Potassium Bromate, Potassium Bromide, Potassium Chlorate, Potassium Iodate, Potassium Iodide, Sodium Acetate, Sodium Bismuthate By W. D. Collins, H. V. Farr, J o s e p h Rosin, G . C. Spencer, a n d Edward Wichers COMMITTEE
O N . ~ N A L Y T I C . A L REAGENTS. AMERICAN
HE specifications given below are intended t o serve for
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reagents to be used in careful analytical work. The limits and tests are based'on published work, on the experience of members of the committee in the examination of reagent chemicals on the market, and on studies of the tests made by members of the committee as the various items were considered. Suggestions for improvement of the specifications will be welcomed by the committee. In all the directions the acids and ammonium hydroxide referred to are of full strength unless dilution is specified; dilution 3) means 1 volume of the reagent or strong indicated as (1 solution with 3 volumes of water; "water" means distilled water of a grade suitable for the test described; reagents used in making the tests are supposed t o be of the grade recommended below or in previous publications? from the committee. A time of 5 minutes is t o be allowed for the appearance of precipitates and before observation of color reactions, unless some other time is specified.
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Ammonium Nitrate REQUIREMENTS Insoluble .\fatttr-h-ot more t h a n 0.005 per cent. Non-volatile Malfer-Not more t h a n 0.010 per cent. Free Acid-To pass test. Chloride (Cl)-Not more than 0.0005 per cent. Sitrife (NO*)-To pass test (limit about 0.0005 per cent). Phosphate (PO+--hTot more t h a n 0.0005 per cent. Sulfate (SO+-Not more t h a n 0.002per cent. Heaoy Metals-To pass test (limit a b o u t 0.0005 per cent lead). Iron-To pass test (limit about 0.0002 per cent).
TESTS Insoluble Matter-Dissolve 10 grams in 50 cc. of water a n d allow t o stand on t h e steam b a t h for 1 hour. Filter through asbestos in a Gooch crucible, wash, dry a t 105' t o 110' C . , a n d weigh. T h e residue should n o t weigh more than 0.0005 gram. Non-volatile Mailer-Heat 10 grams gently till t h e salt is volatilized a n d ignite 5 minutes a t cherry redness. T h e residue should not weigh more than 0.0010 gram. Free Acid-Dissolve 5 grams in 50 cc. of strictly carbon dioxide-free water a n d a d d 1 drop of methyl red solution. No red color should be produced. Chloride-Dissolve 2 grams i n 20 cc. of water, a d d 1 cc. of nitric acid a n d 0.5 cc. of 0.1 N silver nitrate. Any turbidity produced should n o t be greater t h a n is produced b y 0.01 mg. of chloride ion in t h e same volume of solution containing t h e quantities of reagents used in t h e test. Nilrife-Dissolve 1 gram i n 10 cc. of water, a d d 1 cc. of 10 per cent sulfuric acid a n d 1 cc. of colorless 0.5 per cent m-phenylenediamine hydrochloride solution. X o yellowish or brownish color should be produced in 5 minutes. Note-m-Phenylenediamine hydrochloride solution can be decolorized b y treating with a little decolorizing black a n d filtering. Phosphale-Dissolve 20 grams i n 50 cc. of water, add 0.8 cc. of nitric acid a n d 50 cc. of ammonium molybdate solution. Shake a t a temperature of about 40' C. for 5 minutes a n d allow t o stand for half a n hour. Any precipitate formed should b e less t h a n is produced when a Quantity of an 1 Presented in connection with t h e report of t h e Committee on Analytical Reagents a t the 73rd Meeting of t h e American Chemical Society, Richmond, Va., April 11 t o 16, 1927. * THIS J O U R N A L , 17, 756 (1925); 18, 636, 759 (1926).
CHEBIICAI, S O C I H T 1 '
alkaline phosphate containing 0.10 mg. of phosphate (PO') is treated according t o t h e above procedure. T h e ammonium molybdate solution is prepared a s follows: Solution (1). Mix thoroughly 100 grams of 88 per cent molybdic acid with 240 cc. of water a n d then a d d 140 cc. of ammonium hydroxide. Filter a n d a d d 60 cc. of concentrated nitric acid. Solution (2). Add 400 cc. of concentrated nitric acid t o 960 cc. of water. When t h e two solutions have cooled, a d d solution ( 1 ) t o solution (2), stirring constantly. Then a d d 0.1 gram of ammonium phosphate dissolved in 10 cc. of water. Stir t h e solution a n d allow t o stand 24 hours before filtering o u t t h e yellow precipitate. 5 grams with 20 cc. of hydrochloric acid in a 500-cc. Sulfate-Digest Kjeldahl flask (not previously used lor sulfuric acid digestions) heated over a low flame. Renew t h e hydrochloric acid lost b y evaporation and continue t h e heating till a piece of starch-iodide paper is only slightly colored b y t h e vapors. Transfer t h e mixture from t h e flask t o a 100-cc. beaker with a little water and evaporate t o dryness on a steam bath. Take up in a little water a n d 2 cc. dilute hydrochloric acid (1 volume of strong acid in 20), filter if necessary, make t o a volume of 20 cc. a n d a d d 2 cc. of 10 per cent barium chloride solution. T h e turbidity should not be greater t h a n is produced b y 0.1 mg. of sulfate (SO,) in a n alka!i salt which h a s been treated with t h e quantities of hydrochloric acid a n d other reagents used in t h e test. Heaoy Metals-Dissolve 2 grams in 40 cc. of water, a d d 0.5 cc. of glacial acetic acid a n d 10 cc. of hydrogen sulfide water. T h e solution should not be darkened. Iron-Add ammonium hydroxide t o t h e solution obtained in t h e test for heavy metals. Any greenish color observed should not be greater than is produced b y 0.004 mg. of iron in a n alkaline sulfide solution.
A m m o n i u m P h o s p h a t e Dibasic ( D i a m m o n i u m Hydrogen Phosphate) REQUIREMENTS
Insoluble Matter-Not more t h a n 0.015 per cent. Reaction to Phenolphthalein-Alkaline. Chloride (Cl)-Not more t h a n 0.001 per cent. Nitrate (NOs)-To pass test (limit about 0.001 per cent). Sulfur Compounds ( a s SUd)-Not more t h a n 0.004per cent. Alkali Salts-Not more t h a n 0.10 per cent. Arsenic (As)-Not more t h a n 0.0002 per cent. Heavy Metals-To pass test (limit about 0.001 per cent lead). Iron-To pass test (limit about 0.002 per cent).
TESTS Insoluble Malter-Dissolve 10 grams in 50 cc. of water a n d allow to stand on t h e steam b a t h for 1 hour. Filter through asbestos in a Gooch crucible, dry a t 105' t o 110' C., and weigh. T h e weight of t h e residue should not be more t h a n 0.0015 gram. Reaction to Phenolphthalein-A solution of 1 gram in 10 cc. of water should b e colored pink b y t h e addition of 2 drops of phenolphthalein solution. Chloride-Dissolve 2 grams in 20 cc. of water, a d d 3 CC. of nitric acid a n d 1 cc. of 0.1 N silver nitrate solution. T h e turbidity should not be greater t h a n t h a t produced b y 0.02 mg. of chloride ion in a n equal volume of solution containing t h e quantities of nitric acid a n d silver nitrate used in t h e test. Nitrate-Mix 3 grams with 2 cc. of water containing 5 mg. of sodium chloride. Add 1 drop of tested indigo solution (1 in 1000) a n d 10 cc. of sulfuric acid, a n d stir till all t h e phosphate is in solution. T h e color should not be completely discharged in 10 minutes. Sulfur Compounds-Dissolve 10 grams in about 80 cc. of water, add 5 cc. of bromine water, bring t o a boil, add 12 cc. of hydrochloric acid, boil, a d d 5 cc. of 10 per cent barium chloride, a n d allow t o stand overnight. If a precipitate is formed, filter, wash, ignite, a n d weigh. The weight of the precipitate should not be more t h a n 0.0010 gram. Alakli Salts-Dissolve 3 grams in 100 cc. of water a n d a d d a solution of 15 grams of lead acetate in 50 cc. of water. Filter off 100 cc. a n d pre-
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cipitate the excess of lead with hydrogen sulfide. Filter without washing, evaporate t h e filtrate to dryness, ignite gently, and weigh. The weight of the residue should not be more than 0.0020 gram. Correction must be made for possible alkali salts in the lead acetate by evaporating the residue from a solution of 10 grams from which t h e lead has been precipitated with hydrogen sulfide. If a weighable residue is obtained, i t must be tested for substances precipitated b y ammonium phosphate and a further correction applied. Arsenic-Test a 2-gram sample b y the modified Gutzeit method. Heavy Metals-Dissolve 5 grams in 40 cc. of water, render neutral t o litmus paper, add 1 cc. of hydrochloric acid and 5 cc. of hydrogen sulfide water, and dilute t o 100 cc. Any brown color should not be more than is produced by 0.05 mg. of lead in the same volume of a solution containing t h e quantities of hydrogen sulfide and excess hydrochloric acid used in t h e test. Iron-Dissolve 2.5 grams in 100 cc. of water. Dilute 10 cc. of the solution to 40 cc., add 1 cc of ammonium hydroxide and 5 cc. of hydrogen sulfide water. A n y green color should not be greater than is produced by 0.005 mg. of iron in a n equal volume of alkaline solution when 5 cc. of hydrogen sulfide water are added.
Barium Carbonate REQUIREMENTS
Matte7 Insoluble in Hydrochloric Acid-Not more than 0.020 per cent. Chloride (C1)-Not more than 0.002 per cent. Hydroxide and Alkali Carbonate-To pass test. Nitrate (A'Oa)-To pass test (limit about 0.003 per cent). Sulfide (S)-To pass test (limit about 0.001 per cent). Calcium and Alkali Salts (as sulfaf.5s)-Not more than 0.30 per cent. Slronlium and Calcium Salts (as sulfates)-Not more than 0.30 per cent. Heavy Metals-To pass test (limit about 0.001 per cent lead). Iron-To pass test (limit about 0.002 per cent iron). Tesrs Matter Insoluble i n Hydrochloric Acid-Dissolve 5 grams in 50 cc. of water and 5 cc. of hydrochloric acid. Dilute to 100 cc., filter through asbestos in a Gooch crucible, dry a t 105' t o 110' C., and weigh. The weight of t h e residue should not exceed 0.0010 gram. C k l o r i d c T o 1 gram of t h e sample add 20 cc. of water and gradually add, with stirring, 1 cc. of nitric acid. Filter if necessary, wash with a little hot water, make t o 30 cc., a n d add 1 cc. of 0.1 N silver nitrate solution. Any turhidity produced should not be greater than is produced b y 0.02 mg. of chloride ion in a n equal volume of solution containing t h e quantities of reagents used in the test. Hydroxide and Alkali Carbonate-Shake 5 grams of the sample for 5 minutes with 50 cc. of warm carbon dioxide-free water, cool, and filter. T o 30 cc. of t h e filtrate add 2 drops of phenolphthalein indicator solution. If a pink color is produced i t should be discharged b y 1 drop of 0.1 N hydrochloric acid. N i t r a t c D i s s o l v e 2.5 grams in mixture of 18 cc. of water and 5 CC. of glacial acetic acid. Add t o t h e solution 2 cc. of sulfuric acid and filter. T o 10 cc. of t h e filtrate a d d 5 mg. of sodium chloride, 2 drops of indigo solution (1 in l O O O ) , and 10 cc. of sulfuric acid. T h e blue color should not be entirely destroyed in 5 minutes. S u l C d c D i s s o l v e 1 gram in a mixture of 8 cc. of water and 2 cc. of glacial acetic acid. As soon a s solution is effected, add 1 cc. of 0.1 N silver nitrate. T h e solution should not darken in 5 minutes. CQlCiUm and Alkali Salts (as sulfates)-Dissolve 2 grams in 30 cc. of water and 3 cc. of hydrochloric acid, dilute t o 80 cc., heat t o boiling, a n d add 15 cc. of 2 N sulfuric acid. Cool, make up t o 100 cc., mix well, a n d allow t o stand overnight. Decant through a dry filter paper, evaporate 50 CC. of the filtrate t o dryness, ignite, and weigh. The weight of t h e residue should not exceed 0.0030 gram. Slronlium and Calrium Salts (as sulfales)-Dissolve 2 grams in 20 cc. of water and 3 cc. of hydrochloric acid and evaporate the solution t o dryness. Powder the residue and add 20 cc. of absolute alcohol. Allow to stand for 30 minutes with occasional shaking. Filter, evaporate the filtrate to a few cubic centimeters, add about 1 cc. of dilute sulfuric acid, evaporate t o dryness, ignite, and weigh. The weight of the residue should not exceed 0.0060 gram. Heavy Metals-Heat 5 grams with 35 cc. of water and add hydrochloric acid drop by drop till the barium carbonate is dissolved, dilute to 50 cc., a d d 1 cc. of hydrochloric acid, and boil (solution A). T o 20 cc. of solution A add 5 cc. of hydrogen sulfide water. Any darkening should not be greater than t h a t produced b y 0.02 mg. of lead under similar conditions. Iron-Dilute 10 cc. of solution A prepared for the above test t o 50 cc., a d d 2 cc. of ammonium hydroxide and 5 cc. of hydrogen sulfide water. Any green color produced should not be greater than is produced by 0.02 m g . of iron in a n equal volume of alkaline sulfide solution.
Barium Hydroxide [Ba(OH)2.8H20] REQUIREMENTS
Assay and Carbonale--Not lese than 97 per cent Ba(OH)r.SHzO; not more than 3 per cent BaCOs.
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Insoluble in Hydrochloric Acid--Not more than 0.010 per cent. Chloride (Cl)-Not more than 0.002 per cent. Sulfide (S)-To pass test (limit about 0.001 per cent). more than 0.20 per cent. Calcium and Alkali Salts ( Q S sulfates)-Not Heavy Afelals-To pass test (limit about 0.0005 per cent lead), Iron (Fe)-To pass test (limit about 0.001 per cent).
TESTS Assay and Carbonale-Weigh 4 t o 5 grams of clear crystals and dissolve in about 200 cc. of strictly carbon dioxide-free water. Titrate with normal hydrochloric acid, using phenolphthalein indicator t o determine the total hydroxide, and continue t h e titration with methyl orange t o determine the total alkalinity. The difference between the two titrations is the barium carbonate. InSOlUbk i n Hydrochloric Arid-Dissolve 10 grams in 10 cc. of hydrochloric acid. Heat on the water bath for 1 hour, filter, through asbestos in a Gooch crucible, dry a t 105' t o 110' C., and weigh. The weight of the residue should not be more than 0,0010 gram. Clzlovide-Treat 1 gram with 25 cc. of water. cautiously add nitric acid until neutral, and a d d an excess of 3 drops. Filter the solution if i t is not perfectly clear. T o the clear solution add 1 cc. of 0.1 N silver nitrate. Any turbidity produced should not be greater than is produced by 0.02 mg. of chloride ion in an equal volume of water containing the quantities of reagents used in the test. Sulfide-Dissolve 1 gram in 8 cc. of water, add 5 drops of alkaline lead solution (made by adding sodium .hydroxide t o a 10 per cent lead acetate solution t i l l the precipitate is redissolved) and 2 cc. of glacial acetic acid. No darkening should be produced. Calcium and Alkali Salts-Dissolve 5 grams in 150 cc. of hot water and 5 cc. of hydrochloric acid. Heat t o boiling a n d add 25 cc. of 2 N sulfuric acid. Allow t o cool, make up t o 250 cc., and allow to stand overnight. Decant 100 cc. through a filter, evaporate to dryness, ignite, and weigh. The weight of the ignited residue should not be more than 0.0040 gram. Heauy &felak-Dissolve 5 grams in 40 cc. of water with sufficient hydrochloric acid t o neutralize t h e solution. Add a n excess of 1 cc. of N hydrochloric acid and dilute t o 50 cc. (solution A). T o 20 cc. of solution A add 5 cc. of hydrogen sulfide water. Any darkening should not be greater than is produced b y 0.01 mg. of lead with the concentrations of reagents used i s the test. Iron-Dilute 10 cc. of solution A t o 50 cc., add 2 cc. of ammonium hydroxide and 5 cc. of hydrogen sulfide water. Any green color produced should not be greater than is produced b y 0.01 mg. of iron in the same volume of an alkaline sulfide solution.
Cupric Sulfate REQUIREMENTS Insoluble Matter-Not more than 0.010per cent. Chloride (Cl)-To pass test (limit about 0.001 per cent). Substances Not Precipitated by Hydrogen Sulfide-Not more than 0.10 per cent. Ammonium Hydroxide Precipitate-Not more than 0.01 per cent. Ammonium Sulfide Metals Other than Iron-To pass test (limit about 0.01 per cent nickel).
TESTS Insoluble Abfatler-Dissolve 10 grams in 100 cc. of water and allow to stand on t h e steam bath for 1 hour. Filter through asbestos in a Gooch crucible, dry a t 105O to 110' C., and weigh. The weight of the residue should not be tnore than 0.0010 gram. Chloride-Dissolve 1 gram in 20 cc. of wnter, add 1 cc. of nitric acid and 1 cc. of 0.1 N silver nitrate. Any turbidity should not be greater than is produced by 0.01 mg. of chloride ion in an equal volume of water with the quantities of nitric acid and silver nitrate used in the test. Substances Not Prccipilated by Hydrogen Sulfide-Dissolve 4 grams in about 190 cc. ot water, add 2 cc. of hydrochloric acid, warm the solution to 60° to 70' C., and pirss hydrogen sulfide till all the copper is precipitated. Dilute to 200 cc. and filter without washing. Evaporate 175 cc. of the filtrate t o dryness, ignite, a n d weigh. The weight of the residue should not be more than 0.0035gram. Ammonium Hydroxide Precipitate-Treat the residue from the previous test with 2 cc. of hydrochloric acid and a few drops of nitric acid and evaporate almost to dryness. Take up with 10 drops of hydrochloric acid and 10 cc. of water, filter, if necessary, and wash the filter paper with a few cubic centimeters of water. Add t o t h e filtrate a slight excess of ammonium hydroxide and heat for 2 minutes. If a precipitate is fprmed, filter through a small filter paper, wash with small quantities of hot water, ignite, and weigh. The ignited residue should not weigh more than 0.0004 gram. Ammonium Sulfide Metals Other than Iron-Dilute the filtrate and washings obtained in the previous test t o 100 cc. Take 10 cc., dilute to 20 cc., and add 1 cc. of hydrogen sulfide water. The solution should not be darkened.
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May, 1927
Lead Dioxide
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Iron-To pass test (limit a b o u t 0.002 per cent). Sodium (Sa)-To pass test (limit about 0.03 per cent).
REQKXREMEXTS Assay--Not less than 90 per cent PbO?. Acid-Insoluble Matter-Not more than 0.30 per cent. Carbonaie (COa)-Not more t h a n 0.03 per cent. Ch!oride (C2)-Not more than 0.002 per cent. n'itvate (S0s)-To pass test (limit about 0.005 per cent). Sulfo!e (SOI)--Not more t h a n 0.10 per cent. Manganese (Mn)-h'ot more t h a n 0.0003 per cent. Other Hydrogen Sulfide Metals-To pass test. Substances Not Precipitaled by Hydvoaen Sul$de--Sot more than 0.50 per cent.
TESTS Assay-Treat 0.5 gram with 15 cc. of dilute nitric acid (1 4- l ) , add from t h e pipet 20 cc. of hydrogen peroxide solution (1 volume of 3 per cent H?Oz and 3 volumes of water) and stir till solution is complete. Solution can be hastened, if necessary, b y t h e addition of 100 cc. of warm water. Titrate t h e excess of hydrogen peroxide with 0.1 iN potassium permanganate. 4 t t h e same time titrate 20 cc. of the hydrogen peroxide treated with 15 cc. of t h e 1 1 nitric acid. T h e difference between t h e two titrations is t h e permanganate equivalent of the PbOz in t h e 0.5-gram sample. Acid-Insoluble Matter-To 1 gram of t h e sample a d d 25 cc. of water and 3 cc. of nitric acid: a d d with stirring 5 cc. of hydrogen peroxide or more, if needed, t o dissolve all t h e lead dioxide. Filter through asbestos in a Gooch crucible, wash, dry a t 105' t o 110' C.,a n d weigh. T h e residue should not weigh more t h a n 0.0030 gram. Reserve the filtrate t o test for substances not precipitated b y hydrogen sulfide. Carbonate (COI)-Place 1 gram in a 1 5 b y 125-mm. hard-glass test tube provided with a stopper a n d bent outlet tube. Ignite a n d pass t h e evolved gases i n t o 10 cc. of saturated barium hydroxide solution diluted t o 50 cc. T h e turbidity should not be greater than is produced in a similar solution of barium hydroxide b y 1 cc. of 0.01 N sodium carbonate solution. Chloride-Warm 3 grams with 25 cc. of water a n d 3 cc. of nitric acid a t about 70' C.f o r 10 minutes, stir well, dilute to 30 cc., a n d allow t o settle. To 20 cc. of t h e clear liquid a d d 1 cc. of 0.1N silver nitrate. The turbidity should not he greater than is produced b y 0.04 mg. of chloride ion in 20 cc. of water containing 2 cc. of nitric acid when 1 cc. of 0.1 N silver nitrate is added. Nitrate-Boil 2 grams with a mixture of 10 cc. of 36 per cent acetic acid a n d 10 cc. of water for 5 minutes. Cool, dilute t o t h e original volume, and filter. Overlay 10 cc. of t h e clear filtrate on 10 cc. of diphenylamine solution (0.5 gram in 100 cc. of sulfuric acid a n d 20 cc. of water). No blue ring should develop between t h e t w o solutions in 20 minutes. ."u!fale-Decompose 4 grams with 10 cc. of hydrochloric acid a n d 3 cc. of nitric acid a n d evaporate t o dryness on t h e steam bath. Add 25 cc. of water a n d 4 grams of sodium carbonate and digest o n t h e steam bath for several hours with occasional stirring. Dilute t o 100 cc. a n d filter. Neutralize 50 cc. of t h e filtrate with hydrochloric acid a n d a d d a n excess 3). Add 10 cc. of 10 per cent barium chloride of 1 cc. of dilute acid (1 solution a n d digest on t h e steam b a t h overnight; filter, ignite, a n d weigh. T h e ignited precipitate should not weigh more t h a n 0.0050 gram. Manganese-Decompose 5 grams with 1 5 cc. of hydrochloric acid. Add 10 CC. of sulfuric acid a n d evaporate t o fumes. Cool a n d cautiously a d d 20 cc. of water. Add 0.5 gram of lead dioxide, heat on t h e steam b a t h f o r 5 minutes, dilute t o 50 cc., a n d filter through asbestos. T h e color should not be greater t h a n is produced b y 0.015 mg. of manganese treated with t h e quantities of the acids and reagent used intesting thesample. Other Hydrogen Sulfide 2~elals-Dissolve 0.5 gram in 3 cc. of nitric acid and 10 CC. of 3 per cent hydrogen peroxide solution. Add 5 cc. of sulfuric acid and evaporate t o fumes. Cautiously dilute to 50 cc. a n d allow to stand until the solution is cool and the precipitate has settled. Filter b u t do not wash. Pass hydrogen sulfide through t h e filtrate. N o red color should be produced a n d a n y darkening should not be greater t h a n is produced by 0 . 1 mg. of lead in t h e same volume of solution when hydrogen sulfide is added. Substances S o t Precipilated by Hydrogen Sulfide-Evaporate t h e filt r a t e obtained in t h e test for acid-insoluble matter t o dryness, moisten the residue with 5 drops of hydrochloric acid, dissolve in 1011cc. of water, pass hydrogen sulfide t o precipitate all t h e lead. Filter, without washing, evaporate the filtrate t o dryness, ignite gently, and weigh. The weight of t h e residue a f t e r correcting f o r t h e non-volatile matter in the hydrogen peroxide should not be more t h a n 0,0050 gram.
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Potassium Bromate REQUIREMEXTS Assaj.-h-ot less than 99.8 per cent KBrOz. Insoluble .k'atlev-Not more t h a n 0.005 per cent. h'eutralrly-To pass test. Bromide (Ev)-To pass test (limit about 0.05 per cent). Xitrogen Compounds ( Q S S)--Not more t h a n 0,001 per cent. Sulfate (SO4)--Not more t h a n 0.005 per cent. H e a v y Metals-To pass test (limit about 0.0006 per cent lead).
TESTS Assay-Dry a powdered sample t o constant weight, weigh out about 0.1 gram, dissolve in 25 cc. of wpter, a d d 3 grams of potassium iodide, followed by 3 cc. of hydrochloric acid. Allow t o stand 5 minutes a n d titrate t h e liberated iodine with 0.1 N sodium thiosulfate. R u n a blank with t h e reagents a n d make t h e necessary corrections. Insoluble Matter-Dissolve 10 grams in 150 cc. of hot water. Filter on asbestos In a Gooch crucible, wash, dry a t 105' t o 110' C.,a n d weigh. T h e weight of the residue should not he more t h a n 0.0006 gram. .VeutraZi!y-To a solution of 5 grams in 60 cc. of warm water a d d 3 drops of phenolphthalein solution. N o pink color should be produced. 4 d d 1 drop of 0.1 A' sodium hydroxide. A pink color should be produced. Bromide-Dissolve 4 grams in 80 cc. of water and divide t h e solution into two equal portions. Add 5 drops of N sulfuric acid t o one portion. At t h e end of 2 minutes this solution should have no more yellow color t h a n t h e solution t o which no acid was added. Nitrogen Compounds-Dissolve 2 grams in 40 cc. of water a n d a d d 10 cc. of 10 per cent sodium hydroxide solution and about 0.5 gram of aluminum wire or foil in small pieces. Allow t o stand for 3 hours protected from loss or access of ammonia. T o one-half of t h e clear liquid a d d 2 cc. of Nessler's solution. T h e color should not be greater t h a n is produced in a similar aliquot of a solution obtained b y treating a quantity of ammonia salt corresponding t o 0.02 mg. of nitrogen (N) with the quantities of water a n d reagents used in t h e test. Sulfate-Evaporate 5 grams t o dryness with 20 cc. of hydrochloric acid a n d repeat the evaporation with 10 cc. Dissolve t h e residue in 50 cc. of water, add 1cc. of dilute hydrochloric acid (1 strong acid and 3 volumes of water), filter, heat t o boiling, a d d 5 cc. of 10 per cent barium chloride solution, and allow to stand overnight. Filter, wash, ignite, a n d weigh the precipitate. T h e weight of t h e barium sulfate should not be more than 0.0006 gram. Heavy Meials-Evaporate 2 grams t o dryness with 10 cc. of hydrochloric acid a n d repeat using 5 cc. Dissolve the residue in 20 cc. of water, neutralize with dilute ammonia, if necessary, a d d 1 cc. of 0.1 N hydrochloric acid, a n d pass hydrogen sulfide through t h e solution. No brown color should be produced. Iron-Add ammonium hydroxide t o t h e solution which ha5 been tested for heavy metals to make i t alkaline. Any green color produced should not be greater t h a n is produced b y 0.04 mg. of iron in a n alkaline sulfide solution. Sodium-Test a warm 10 per cent solution in the flame with a platinum wire. N o pronounced yellow color should be produced.
Potassium Bromide REQUXREMEXTS Insoluble Malfer-Not more than 0.005 per cent. A'eutrality-To pass test. Bromate (BrOs)-To pass test (limit about 0.001 per cent). Chloride (Cl)--Not more than 0.4 per cent. more than 0.001 per cent. Nitrogen Compounds (as N)-Not Sulfate (SO&-Not more t h a n 0.005 per cent. pass test (limit about 0.003 per cent). Barium (&)-To Calcium, Macnesium, and Ammonium Hydroxide Precipilale-Not more t h a n 0.005 per cent. Heaoy Metals-To pass test (limit about 0.0005 per cent lead). Iron (Fe)-To pass test (limit about 0.0005 per cent).
TESTS Insoluble Matter-Dissolve 10 grams in 50 cc. of hot water. Filter through asbestos in a Gooch crucible, wash with hot water, dry a t 105' t o 110' C., a n d weigh. The weight of the residue should not exceed 0,0005 gram. Areutrality-A solution of 5 grams in 30 cc. of water should not require more t h a n 0.05 cc. of 0.1 N hydrochloric acid t o make i t neutral t o methyl orange indicator. Bvomate-Dissolve 1 gram in 10 cc. of freshly boiled and cooled water, a d d 2 drops of 10 per cent potassium iodide solution, 1 cc. cf freshly made starch solution, a n d 5 drops of ?,' sulfuric acid. KO blue or violet color should be produced a f t e r standing 10 minutes a t 25' C. Chloride-Dry a sample t o constant weight a t 105' to l l O o C.,weigh accurately about 0.5 gram and dissolve i t in about 175 cc. of water. Run in slowly with constant stirring 50 cc. of 0.1 S +ilver nitrate. Add 5 cc. of nitric acid, dilute t o 250 cc. a n d mix well. Filter through unmoistened filter paper into a dry flask, rejecting t h e first 10 or 20 cc. Titrate 100 cr. of t h e subsequent filtrate with 0 . 1 N ammonium thiocyanate using ferric ammonium sulfate indicator. h-ot more t h a n 84.4 cc. of 0 . 1 S silver nitrate should be consumed per gram of potassium bromide. Xitrogen Compounds-Dissolve 2 grams in 40 cc. of water in a flask, Add 10 cc. of 10 per cent sodium hydroxide solution a n d about 0.5 gram of aluminum wire in small pieces. Allow t o stand for 3 hours protected from access or loss of ammonia. 4 d d 2 cc. of Nessler's solution to half of
I,VDUSTRIAL A N D EiVGIhTEERI.VG CHEMISTRY
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the clear liquid. The color should not be greater than t h a t produced by a quantity of a n ammonium salt containing 0.01 mg. of nitrogen. Correction must be made for nitrogen i n the water and sodium hydroxide used, Sulfate-Dissolve 10 cc. in 100 cc. of water, add 1 cc. of 10 per cent hydrochloric acid, and boil. Add 5 cc. of 10 per cent barium chloride solution, allow t o stand overnight, filter, wash, ignite, and weigh. The weight of the barium sulfate should not exceed 0.0012 gram, Barium-Dissolve 4 grams in 20 cc. of water, filter if necessary, and divide in two portions. To one portion a d d 2 cc. of 10 per cent sulfuric acid and to t h e other add 2 cc. of water. The solutions should be equally clear a t t h e end of 2 hours. Calcium, Magnesium, and Ammonium Hydroxide Preciprtate-Dissolve 10 grams in 75 cc. of water, a d d 5 cc. of 4 per cent ammonium oxalate solution, 2 cc. of 10 per cent ammonium phosphate solution, and 10 cc. of ammonium hydroxide. Allow t o stand overnight, filter, wash with water containing 2.5 per cent of ammonia, ignite, and weigh. The weight should not exceed 0.0005 gram. Heavy Melals-Dissolve 2 grams in 20 cc. of water and pass hydrogen sulfide through the solution. N o brown color should be produced. Iron-Add ammonium hydroxide to the solution tested for heavy metals till i t is slightly alkaline. Any green color should not be greater than is produced b y 0.10 mg. of iron in a n equal volume of alkaline sulfide solution.
Potassium Chlorate REQUIREMENTS
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Insoluble Matter-Not more than 0.005 per ceat. Bromate (Br0s)-Not more than 0.015 per cent, Chloride (C1)-Not more than 0.001per cent. Nitrogen Compounds (as N)-Not more than 0.001 per cent. Sulfate (SO+-To pass test (limit about 0.002 per cent). Arsenic (As)-Not more than 0.00005 per cent. Calcium, Magnesium, and Ammonium Hydroxide P r e c i p i l a l c N o t more than 0.005 per cent. Heavy Melals-To pass test (limit about 0.0005 per cent lead). Iron (Fe)-To pass test (limit about 0.0003 per cent). Sodium (Na)-To pass test (limit about 0.02 per cent).
TESTS Insoluble Matter-Dissolve 10 grams in 200 cc. of hot water and allow to stand on the steam bath for 1 hour. Filter through asbestos in a Gooch crucible, wash, dry a t 105' to 110' C . , a n d weigh. The weight of t h e residue should not be more than 0.0005gram. B r o m a f c D i s s o l v e 4 grams in 200 CC. of cold, oxygen-free water in a 400- t o 500-cc. bottle. Add 10 cc. of N hydrochloric acid, mix well, then a d d 10 cc. of freshly prepared 10 per cent potassium iodide solution and 5 cc. of freshly prepared 5 per cent starch solution. Stopper t h e flask, set aside for 1 hour in R dark place, and then titrate the liberated iodine with 0.1 N sodium thiosulfate. Prepare a n identical blank without t h e chlorate using the same sized flask. Titrate t h e iodine liberated in t h e blank and subtract the volume of thiosulfate consumed in the blank from the volume of thiosulfate consumed in t h e test. T h e difference should not be more t h a n 0.3 cc. of 0.1 N thiosulfate. Chloride-Dissolve 2 grams in 40 cc. of warm water; cool, a d d 5 drops of nitric acid, free from lower oxides of nitrogen, and a d d 1 cc. of 0.1 N silver nitrate. The turbidity should not be greater than is produced b y 0.02 mg. of chloride ion in an equal volume of water with t h e quantities of acid a n d silver nitrate used in the test. Nitrogen Compounds-Dissolve 2 grams in 40 cc. of warm water, cool, add 10 cc. of 10 per cent sodium hydroxide a n d 0.5 gram of aluminum wire in small pieces, and allow t o stand for 3 hours protected from escape or access of ammonia. Decant 25 cc. and add t o i t 2 cc. of Nessler's solution, The color produced should not be greater than is produced b y a quantity of an ammonium salt corresponding t o 0.01 mg. oi nitrogen when treated in the same manner a s the 2-gram sample. Sulfate-Dissolve 5 grams in 150 cc. of water, a d d 1cc. of dilute hydrochloric acid (1 4) a n d 6 cc. of 10 per cent barium chloride. No precipitate should be produced on standing overnight. Arsenic-Evaporate 2 grams with 10 cc. of hydrochloric acid until no more chlorine is evolved a n d apply to t h e residue t h e modified Gutzeit test. Calcium, Magnesium, and Ammonium Hydroxide P r e c i p i l a t c B o i l 10 grams with 50 cc. of water a n d 25 cc. of hydrochloric acid until no more chlorine is evolved. Dilute t o about 60 cc., heat t o boiling, a d d 5 cc. of 4 per cent ammonium oxalate solution, 2 cc. of 10 per cent ammonium phosphate solution, and 15 cc. of ammonium hydroxide. Allow t o stand overnight, filter, wash with water containing 2.6 per cent of ammonia, ignite, a n d weigh. The weight of the residue should not be more than 0.0005 gram. Heaoy Metals-To 2 grams add 5 cc. of water and 5 cc. of hydrochloric acid and evaporate to dryness on t h e water bath. Dissolve the residue in 25 cc. of water, neutralize with ammonium hydroxide if necessary, add 1cc. of 0.1 N hydrochloric acid and pass hydrogen sulfide through the solution. No brown color should be produced.
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Iron-Add ammonium hydroxide to the soliition tested for heavy metals till i t is slightly alkaline. Any green color should not be greater than is produced by 0.06 mg. of iron in a n equal volume of alkaline sulfide solution. Sodium-Test a 10 per cent solution in warm water on a platinum wire in t h e flame. N o pronounced yellow color should be produced.
Potassium Iodate REQUIREMENTS Insoluble Matter-Not more than 0.005 per cent. Neutrality-To pass test. Chlorate (Cl0s)-To pass test (limit about 0.01 per cent). Chloride and Bromide-To pass test (limit about 0.02 per cent a s CI). Iodide (I)-To pass test (limit about 0.01 per cent). Nitrogen Compounds (as N)-Not more than 0.005 per cent. Sulfate (SO
