Qualitative uaivsis (Hmmll Hmvmitg Jih^tJg THE GIFT OF TrvoS! . ..ex...^.«...^.cJl^.w45ll.. ■A.. AA-Q.'^k^ \Q^\-\\.o.( Cornell University Library arV19348 A Short course in qualita''Y;?,„lF,™™!?,?iiii^ 3 1924 031 276 029 olin.anx Cornell University Library The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924031276029 Short Course Qualitative Chemical Analysis. BY JOHN H. APPLETON, A. M., PROFESSOR OF CHEMISTRY IN BROWN UNIVERSITY. THIRD EDITION, PHILADELPHIA COWPERTHWAIT & CO. 1878. K Copyright, John H. Appleton. 1878. Preface to the Third Edition. The author, having used this little work for several years in his own classes, offers a new and revised edition to his fellow-teachers. The features of the book that are considered of especial importance are — First, its brevity and compactness ; Second, the direct and simple course of analysis pre- scribed ; Third, the large number of formulas and reactions presented. The experienced teacher will at once appreciate the importance of these characteristics. There are many valuable works on this subject, but most of them are too bulky and too costly; so, also, some of the best of them give processes of analysis that are far too complex and involved, for a beginner. As to formulas and reactions, — these are unquestionably of great importance : no matter whether the student is hoping to become an expert professional analyst, or merely to gain mental discipline, he must master reac- tions and formulas if he would really comprehend the subject. The especial aim of the author is to afford a short but instructive course in this fascinating branch of Chemistry. Brown University, September, 1878. Contents. PAGE CHAPTER I.— FIRST GROUP OF METALS 7 Lead, Silver, and Mercury in the mercurous form 7 Additional experiments with First Group metals 12 Common forms of First Group metals 13 CHAPTER H.— SECOND GROUP OF METALS 14 Arsenic, Antimony, and Tin 14 Gold and Platinum 14 Copper, Bismuth, Mercury in the mercuric form, and Cadmium... 14 Additional experiments with Second Group metals 26 Common forms of Second Group metals 28 CHAPTER III.— THIRD GROUP OF METALS 29 Cobalt and Nickel 29 Iron, Manganese, and Chromium 29 Zinc and Aluminum 219 Additional experiments with Third Group metals 38 Common forms of Third Group metals 39 CHAPTER IV.— FOURTH GROUP OF METALS 40 Barium, Strontium, and Calcium 40 Additional experiment 45 Common forms of Fourth Group metals 46 CHAPTER v.— FIFTH GROUP OF METALS 47 Magnesium, Potassium, Sodium, and Ammonium 47 Additional experiments with Fifth Group metals 51 Common forms of Fifth Group metals 52 CHAPTER VI.— TREATMENT OF UNCOMBINED MET- ALS AND METALLIC ALLOYS 53 CHAPTER VII.— DETECTION OF ACIDS AND ACID RADICLES 57 First Group of Acids eg Nitric acid eg Chloric acid 60 Common forms of First Group acids 61 CHAPTER VIII.— SECOND GROUP OF ACIDS 62 Carbonic acid, or Carbonates 5^ Sulphydric acid, or Sulphides 64 Sulphurous acid, or Sulphites gr Cyanohydric acid, or Cyanides (69 and) 66 Common forms of Second Group acids gy 4 CONTENTS. 5 PAGE CHAPTER IX.— THIRD GROUP OF ACIDS 68 Chlorohydric acid, or Chlorides 69 Cyanohydric acid, or Cyanides (66 and) 69 lodohydric acid, or Iodides 70 <• Bromohydric acid, or Bromides 71 Common forms of Third Group acids 7' CHAPTER X.— FOURTH GROUP OF ACIDS 72 Sulphites and Carbonates 73 Sulphuric acid, or Sulphates 73 Oxalic acid, or Oxalates (89, 91, and) 74 Phosphoric acid, or Phosphates (91 and) 76 Chromic acid, or Chromates (gi and) 77 Boracic acid, or Borates 78 Common forms of Fourth Group acids 79 CHAPTER XL— FIFTH GROUP OF ACIDS 80 Silicic acid, or Silicates 80 Fluohydric acid, or Fluorides ... 83 Common forms of Fifth Group acids 83 CHAPTER XII.— SIXTH GROUP OF ACIDS . The Organic acids 84 The General Group test 85 Acetic acid, or Acetates 86 Tartaric acid, or Tartrates .• 86 Citric acid, or Citrates 88 Oxalic acid ^ (74, 91, and) 89 Tannin and Gallic acid J!T 89 CHAPTER XIII.— EXCEPTIONAL OXALATES, BO- RATES, AND PHOSPHATES 91 CHAPTER XIV.— INORGANIC SUBSTANCES, INSOLU- BLE IN ORDINARY REAGENTS 96 CHAPTER XV.— PRELIMINARY EXAMINATION OF UNKNOWN SUBSTANCES 99 Examination of liquids '. 99 Examination of solids loi Examination on charcoal loi, 102 Examination in a closed tube 103 Examination by flame-color tests 104 Examination by Borax bead 104 Examination with solvents...., 105 INDEX 109 1» Qualitative Analysis. CI-IAPT"^R I. FIRST GROUP OF METALS. Description. 1. The first group includes those metals which are precipitated upon addition of Chlorohydric acid (H CI) to their solution. The metals are — Lead, Pb (Plumbum), usually II. (sometimes IV.). Silver, Ag (Argentum), " I. Mercury, (when it is in its inercurous form), Hg^ (Hydrargyrum), II. Types of Compounds. a. Plumbic oxide, 4^ Pb O, Pb =0. Plumbic di-oxide. PbO„ ^^{z%: Argentic chloride. AgCl, Ag —CI. Mercurous chloride. Hg, CI, CI -Hg- -Hg- -Cl. Mercuric compounds belong to the Second group. For if we add Chlo- rohydric acid to a Mercuric compound. Mercuric chloride is formed ; but Mercuric chloride is soluble, hence it does not appear as a precipitate in the First group, but passes on to the next group, where it is precipitated. 7 8 AFPLETON'S QUALITATIVE ANALYSIS. The Process. 3. To the solution to be tested, add a few drops of dilute Chlorohydric acid. If a precipitate appears, thor- oughly agitate the solution, and then allow the" precipi- tat(i.to subside. To the clear liquid add a few more drops of the acid. If no precipitate appears, it shows that enough acid has been used ; but if more precipitate appears, repeat the agitation, etc. just described. It is important to add enough acid, but a large exc^s must be carefully avoided. 4r. The precipitate indicates the probable presence of some member or members of the First group. Filter ; the filtrate may contain soluble chlorides of metals of later groups ; the precipitate contains the in- soluble chlorides of the metals of the First group. It may contain the following compounds : Plumbic chloride, Pb CI2, crystalline; white. Argentic chloride, Ag CI, flocculent ; white, changing to purple or black upon exposure to sunlight. Mercurous chloride, Hgj Clj, .flocculent; white. AgNOj 1 AgCl 1 Pb(N03l2 I + 5HCI = PbCl^ j. + 5HNO3. Hg^ (N O3), J Hg, CI, J 5. Remove the precipitate and boil it in water. Filter. Boil the precipitate in a new portion of water, and agaifi filter. Hot water dissolves the Chloride of lead, but does not dissolve the Chloride of silver nor the Mercurous chloride. (It is important to dissolve the whole of the Plumbic chloride, even if several repeated boilings are necessary.) FIRST GROUP OF METALS. The Filtrate containing Lead. issolved Portion, Tested Jor Strontium, and Calcimn. 98. To the alcoholic filtrate, add dilute Sulphuric acid This produces a white, gelatinous precipitate of Strontic and Calcic sulphates (together with a small amount of Baric sulphate — afforded by the traces (Si Baric chloride, which the alcohol inevitably takes up). Filter the mixture. 6 H CI. Sr CI2 Sr S O^ CaClj -^3H, SO, = Ca S 0^ [BaClj. [Ba S 0.,] 44 APPLETON's qualitativp: analysis. 99. Transfer the precipitate to a casserole, and boil it for five minutes in a mixture of solutions of Sodic carbonate and Potassic sulphate. By this operation, Strontic sul- phate is changed to Strontic carbonate ; Calcic sulphate is changed to Calcic carbonate ; but the Baric sulphate remains unchanged (the Potassic sulphate being the agent which is employed for the purpose of preventing the change, in the case of Baric sulphate). Sr S O^ 1 Sr C O3 Ca S O^ j- + 2Na2C03 + K2S04 = Ca C O3 [BaSOJJ [BaSO^] 2 Naj SO^ K, S O^. Filter; and thoroughly wash the precipitate with hot water. This is for the purpose of removing all Sodic and Potassic sulphates ; it is a step of vital importance to the success of the later processes. 100. Transfer the precipitate from the filter to a test- tube. Add a few drops of pure Chlorohydric acid. The precipitate should dissolve with effervescence. Sr C O3 ) Sr CI, ) Cacoll + -^^^^ = CaC.J + ^ ^ °^ + == «^ °- Filter again. Evaporate the solution almost to dryness. Dissolve the residue in water. Filter yet again. (We have now completely separated and removed all Barium; and we have the Strontium and Calcium as chlorides.) 101. Divide the solution into two parts. First Portion. — To this, add solution of Calcic sul- phate. A white precipitate, appearing either immediately or after a few minutes' application of heat, indicates pres- ence of Strontium. FOURTH GROUP OF METALS. 45 Sr CI, ) Sr S O , 1 ^ I + Ca S O , = M + Ca CI,. Ca CI2 j "* Ca CI, j ^ ' (Of course the first portion should not be tested for Calcium, suice we have added Calcium sulphate to it.) Second Portion. — If Strontium has been foiiiid in the first portion, add Potassic sulphate. This produces both Strontium sulphate and Calcium ^sulphate. Cl, ■) Sr S O- ) 'I + a K, S O. = * f + 4 K Cl. Cl„ ) ^ ' * Ca S O4 j ^ Now, although this process precipitates all the Stron- tium, and part of the Calcium, yet a small quantity of Calcic sulphate (sufficient for its detection) remains in solution. 102. Filter, and to the perfectly clear filtrate, add Am- monic hydrate and Ammonic oxalate, (NH.,)2C204. A white precipitate of Calcic oxalate appears, if Calcium is present. CaSO, + (NHJ2C2O, = CaC, O, + (N HJ, S O,. Note. If, by the test of the first portion, Strontium was shown to be absent, then the second portion may be at once tested for Calcium — and this without addition of Potassic sulphate — the main purpose of the latter reagent, here, being to throw Strontium, when present, out of the solution. Adflitional Experiment. 103. To a water solution of Calcic sulphate (CaSOJ, add Ethylic alcohol ; the Calcic sulphate appears as a white precipitate, because the mixture of alcohol and water, cannot hold dissolved as much of the salt, as water alone c:in. 46 , APPLETON'S QUALITAIUVE ANALYSIS. 104. Common Form,s of Fourth Group Metals. Muriate of Baryta, Baric chloride; white, Ba Clj + 2 H^ O. Nitrate of Baryta, Baric nitrate ; white, Ba (N Ogjj. Heavy spar, natural Baric sulphate; white, Ba S O^^. Muriate of Strontia, Strontic chloride; white, Sr Clj + 3 Hj O. Nitrate of Strontia, Strontic nitrate ; white, Sr (N O^)^. Quick-lime, Calcic-oxide; grayish white, Ca O. Slaked lime, Calcic hydi-ate; white, Ca Oj Hj. Chalk, marble, lime- stone, etc.. Calcic carbonate, Ca C Oj. Gypsum, plaster-of- Paris, land-plaster. Calcic sulphate; white, Ca S O^. Bone-ash, mostly Calcic phosphate, Ca., (P 04)2. Bleaching powder, a mixture of Calcic hypo-chlorite. Calcic chloride and Calcic hydrate, Ca O2 CI2 -f Ca CI2 -I- Ca O^ H^. CHAPTER V. FIFTH GROUP OF METALS. Description. 105. The Fifth Group includes those metals which are left in the solution, after the precipitation and removal of the members of the preceding Groups. metals are — Magnesium, Mg, II, Potassium, K, (Kalium), I. Sodium, Na, (Natrium), I. Ammonium, N Hj, I. (Ammonium is a compound radicle; it is called the hypothetical metal, because it acts chemically the part of a metal, in forming salts, etc.) Types of Compounds, Magnesic, Mg CI3. Potassic, K CI. Sodic, Na CI. Ammonic, N H^ CI. Remarks. Note I. The reason for the above-mentioned metals belonging to this Group, is evidently to be found in the fact that they decline to form insoluble compounds. This peculiarity prevents our detecting them by such a sys- tematic and orderly process as is applicable to the other Groups. 48 APPLETON'S QUALITATIVE ANALYSIS. Note II. It is obvious that our tests for Amm'onium, should 'not be applied to the filtrate from the preceding Groups. For this Bltrate is certain to contain salts of An^monium (from compounds used in the detec- tion of the metals of the Third and Fourth Groups), whether Ammonium salts were present at the beginning or not. The tests for Ammonium must be applied to a portion of the original solution, reserved for the purpose. The Process. 106. The filtrate from the Fourth and preceding Groups must be divided into three parts, and treated as follows : Tixe Test for Magnesium. 107. First Portion. — To this portion add first Am- monia hydrate to alkaline reaction ; then add Hydro-di- sodic phosphate (HNajPOJ. A white precipitate of Ammonio-magnesic phosphate (NH4MgP04) constitutes the test. The precipitate, especially if relatively small in quantity, assumes a distinct crystalline form upon being left to itself for a day or two. (N Hj) Mg CI3 + N H^ O H + H Na^ P O^ = (N H j) Mg P O^ + 2 Na CI -f N H^ CI + H^O. The Test for Sodium (and JPotdssiuin). 108. Second Portion. — Evaporate this portion, almost to dryness. Dip a cleaned platinum wire into the residual drop of liquid, and try it in a lamp-flame with the spec- troscope. 109. Sodium is always detected. (It is always distrib- uted throughout the atmosphere as some salt of Sodium, probably NaCl.) When the spectroscope reveals only a pale orange line, the Sodium must be considered as merely atmospheric. When at the line D, there appears FIFTH GROUP OF lUFTALS. 49 a dazzling orange band, it must be considered the test for Sodium, and as showing the presence of Sodium m the solution under examination. 110. The appearance of a rich, dark-red hne at the left of the Sodium line (near line A), and also, of a diffused spectrum-light through the whole field, and also, of a violet line (at the other end of the spectrum, near H, and difficult of recognition), indicates presence of Potassium. (If much Sodium is present, the Potassium spectrum is difficult of recognition with ordinary laboratory spectro- scopes.) 111. When but one of these metals is present, the color imparted to the flame is very characteristic, so that the metal may be detected without using the spectroscope. Sodium gives a strong orange color. Potassium alone, gives a delicate pinkish-violet shade. For the establishing of this latter shade by comparison, dip another clean platinum wire in pulverized Potassic nitrate ; then hold it in the flame. The proper Potassium flame readily appear.s. Tlie Test fof Potassium. 112. Third Portion. — Evaporate this portion to dry- ness. Then carefully heat the residue to redness. This is to expel Ammonium salts. Cool the vessel. Dissolve the residue in two or three drops of water, and filter through a very small filter. To the filtrate, add a few drops of Platinic chloride (PtCl^). A yellow, granular, and ciystaUine precipitate of Potassio-platinic chloride constitutes the test for Potassium. 2KC1 -I- PtCl^ = (KjPtClJ. (A similar precipitate of (N H4)2 Pt Clg is afforded by Ammonium salts. Hence, in order to be certain that a given precipitate is an indica- 5 so APPLETON'S QUALITATIVE ANAYLSIS. cation of Potassium, we must have previously made sure of the removal of all Ammonium compounds.) The Test for Ammonium. 113. Portion of Original. — To a portion of the origi- nal solution, add Sodic hydrate (NaOH). If Ammonium is present, Ammonia gas (NHj) will be liberated. This gas may be recognized — (a) By its pungent odor; (i^) By its giving a blue color to moist, red litmus-paper suspended in the gas (but not touching the walls of the test-tube) ; (c) By giving heavy, white fumes of NH^Cl when a rod dipped in Chlorohydric acid is suspended in the tube con- taining the escaping gas. (In this latter case, judgment must be exercised, since concentrated Chlorohydric acid gives of itself z.fuine upon exposure to moist air.) N H^ N O3 -f- Na O H = N H3 + Na N O3 -j- H^ O. N H, -i- H CI = N H, CI. Wessler's Test for Aiiimonimn, 114. In a clean retort or side-neck test-tube, place a very small amount of water and a short stick of solid Caustic Soda (NaOH). Connect the apparatus with a test-tube used as a receiver, the latter containing a small amount of water and some Nessler-reagent (described below). Now bring the contents of the retort to full ebullition, for the purpose of making sure that the apparatus and reagents are free from Ammonia. This being assured, add to the FIFTH GROUP OF METALS. S I contents of the retort a small portion of the substance to be tested (either in the sohd or in the hquid form). Then, again bring the contents of the retort to active boiling. If Ammonia is present, it should distill into the Nessler- reagent, and produce a brown precipitate of Di-mecur- ammonium iodide, thus : (2HgI,+4KI)+3KOH + NH3 = (NHg,I + 2H20) + 7KI+H20. Nessler- Reagent. Remarks on Wessler's Test. [a] Prepare Nessler-reagent as follows. Dissolve 17^ ^ in., . . . 10 00 2-5 00 50 00 High School or Academy size, I^A x i% In.. Shelf Specimens, . . . 25 00 50 00 100 00 College size. 3>^ x 6 in.. Shelf Speci- mens. . , 50 00 150 00 300 00 I have now over thirty-five tons, and over $40,000 worth of Minerals, mostly crystallized in stock. It is well recognized that my prices are lower and my speci- mens more accurately labelled than those of any other dealer in the country. This is mainly due to the immense stock I carry (tlie largest in minerals of any in the country), and my system of printed labels attached to the specimens. Catalogue of 2,500 species of Shells, made for me bv Geo. "U'. Tryon, Jr.. who has labelled nearly all my shells, 3 cts. ; printed on heavy paper with genus label list, 10 cts. As the correct naming of the specimens will be the important point to most persons, I feel justified in mentioning that 1 have been a collector of Minerals for fifteen years; that I was a student under Prof. Wolcott Glbbs. at Cambridge, and Trof. A. Hoffman, at Berlin. I was also Instructor at Michigan University, and Professor in the Iowa S. A. College, In Chemistry and Mineralogy, for six years. Send for the Naturalist's Leisure Hour^ giving full particulars. Specimen ftee A. E. FOOTE, M. D., 1223 Belmont Ave,, Philadelphia, Pa,, Professor of Cliemistry and Mineralogy, Fdlow of the American AssociaHmr for the Advaiicemenl of Science; Life Member of the Philadelphia Academy of Natural Sciences, mid of the American MuBeum of Natural History, Central Part:, New I'arA-. In writing please state In what Publication you saw this Advertisement. ESTABLISHED IN 1842. PIEST PREMIUM at FEANKLIN INSTITUTE, 1845. REPORT OF Ji^^T^ Ji^T^lD ^]mitnum\ l[nt^ri|aliotial ||jehiljiiiot[, " The Exhibitor manufactures platinum vessels for laboratory use from the native platinum, which he refines, or scraps. All articles are made from melted platinum and hammered out. Excellence in the quality of platinum apparatus." Approval of Group Judges [Signature of the Judge.] F.A. GENTH. J. LAWREN CE SMITH, F. KUHLMAN , P. DEWILDE, DR. V. WAGNER, E. PATERNO, CHARLES A. JOY, J. W. MALLET. "e5^^