TABLE FOR THE The filtrate from Group I. may contain all other basic It must be freed from HNO,: this may be done by evaporating with slight To the HCl solution, which should be concentrated if it has been rendered too agitated, and allowed to rest for some hours. A yellow crystalline The filtrate should be mixed with a reasonable quantity of precipitate of KPtCl indicates Pt. The largest part of the rare metals R, Ru, Ir, and also some PdCl, A precipitate con- would separate here in brown yellow sponge, indicates Au. the same form. Through the filtrate a current of second and even a third stream of thoroughly washed with hot water S; the undissolved portion must be The residue may contain Hg,S, Pb S, Bi S, Cu,S, Cd,S, and Pd S: it must be washed until quite free from Cl, then boiled in concentrated ÉNO, until all red fumes cease. The liquor is diluted with H,O, the residue allowed to settle, and dilute H2SO, added until precipitation is complete; it is then agitated and filtered. ANALYSIS OF GROUP II. · radicals; in the present Group we separate the following:Pt, R, Ru, Ir, Os*, Au, and Mo. excess of HCl once or twice; in so doing, any Os would escape as osmic anhydride*. dilute, a reasonable quantity of NH4Cl solution should be added, the liquid well concentrated solution of HC2O1, and moderately heated for some hours. HS should now be passed for a considerable time, the liquid warmed, and a HS passed to ensure perfect precipitation. The precipitate must be collected, containing a little HS, then boiled for a few minutes with (NH4)2S containing filtered off. The filtrate may contain Sn, As, and Sb, combined with S, in the form of acid-radicals. Reprecipitate them as sulphides by acidulating with HCl; and, to prevent the HCI from decomposing a portion and dissolving it as chloride, pass a few bubbles of HS through the solution. Collect and wash the precipitate; boil it in HCl, and add, when boiling, a very little HNO,, drop by drop, until it is dissolved. Introduce the solution into an apparatus from which H is being evolved by the action of H2SO, upon Zn, both of these reagents having been ascertained to be free from As; pass the evolved gases through a wash-bottle containing solution of PbÃ, and thence into a test-tube containing a somewhat strong solution of AgNO3, continuing the passage as long as any precipitate is produced in the AgNO, solution. When the action has ceased, a black residue will be found upon the surface of the Zn in the generator t. * The separation of these four metals is most difficult: the process will be described in an Appendix to the present Table. This process was, we believe, originated by Dr. Hofmann, and is employed by him in the Royal College of Chemistry. TABLE FOR THE The precipitate produced by (NH),S in the Zn,S, Mn, S, Fe,S, Co, S, Ni,S, U4S3; Cr2H2O, ALH ̧O„, together with certain phosphates of this group, and certain Boil the precipitate with HCl, and add a few drops of HNO,, drop by drop, excess of KHO solution; The undissolved residue is Al,H,O,, or AlРÓ and indicates Al. To ascertain whether the phosphoric radical is present, dissolve the precipitate in HT, add NH HO in excess, then add NH Cl and MgSO,, when the formation of a white crystalline precipitate would indicate the presence of The solution will con- Fe, Mn, and Y, and Dissolve in a few solution, previously The precipitate would contain the Fe as hydrate; also Mn, Y, Ba, Sr, Ca, and Mg as carbonates. Dissolve in HCl, avoiding any excess, warm, and add (NH), S; filter. The filtrate will contain the Ba, Sr, Ca, and Mg, and must be examined according to the two succeeding Tables. The precipitate will contain the Fe, Mn, and Y. Dissolve in HCl, with the cautious addition of a few drops of HNO3; add excess of KA, and boil until all the Fe is precipitated. The precipitate consists of as basic acetate. Add The solution contains the Mn and Y. NHCl and excess of NH, HO; filter off any YHO which may precipitate, and add to the filtrate a few drops of Br. Allow to rest for twenty-four hours. The brown preci- The solution contains any dissolved, which may be precipitated as oxalate. ANALYSIS OF GROUP III. filtrate from the HS precipitate may contain TaH3O3, Ti2H2O3, G2H3O3, Zr2H303,, Ce2H3O3, LaHO, DiHO, ThHO, YHO, phosphates, borates, and fluorides of Ba, Sr, Ca, and Mg. to the boiling liquid; filter from any residue of S. Add to the cooled solution filter, and wash with cold water. The precipitate may contain Mn, Fe, Co, Ni, U, Ti, Zr, Ce, La, Di, Y, and Th, together with the phosphates, borates, and fluorides. First dissolve in HCl, avoiding excess, and boil the solution for some time; filter. A white precipitate of Ti2O2 indicates the presence of Ti. To the filtrate, some quantity of a saturated solution of K2SO4 is added, the liquid allowed to rest for some hours, filtered, and the precipitate washed with cold saturated solution of K2SO4 The formation of a white, presence of Zr, Ce, La, Di, and Th. The solution is boiled with a few drops of HNO,, slight excess of NH,HO added, and then a warm and concentrated solution of (NH4)2CO3, with which the precipitate formed is digested at a moderate heat for some time. It is then filtered rapidly while hot, and the digestion with (NH1),CO, repeated. The precipitate will contain the also the phosphates, borates, and fluorides. drops of HCl, and drop into boiling KHO mixed with a little Na,Co,. The solution should be examined for phosphoric, boracic, and hydrofluoric acids, by the appropriate tests. The filtrate will contain the U, Ni, and Co, and, if concentrated, will, on cooling, deposit fine lemonyellow crystals of (U,O),CO., (NH4),CO., which may be separated. Add some NH Cl solution, and boil for some time. The precipitate will consist of (U20)20. Test by means of the blowpipe for U. To the filtrate add Na, CO,, and boil until all odour of NH, has ceased, then almost neutralize the Na, CO, with HCl. Add now, gradually, such a quantity of a weak solution of Koy as shall be exactly sufficient to redissolve the precipitate at first produced by it. Boil until HCy ceases to be evolved; filter, if necessary, and, when cold, add some excess of a strong solution of NaCIO*. If no black precipitate or colour appears after the lapse of ten minutes, add a drop of HCI to facilitate its formation. Warm and filter. The precipitate will consist of (Ni),O,. Ni. The filtrate will contain the Co. Eva- * This mode of separation was, we believe, first practised by Dr. Hofmann. TABLE FOR THE ANALYSIS OF GROUP IV. The filtrate from the (NH), S precipitate freed from (NH), S by boiling and filtration, having been mixed with (NH), CO, and warmed in the presence of NH, Cl, may have yielded a precipitate consisting of the carbonates of Ba, Sr, and Ca. The precipitate is dissolved in a few drops of HCl and divided into two portions. The filtrate from Group IV., or the solution in which the various groupreagents have failed to produce any precipitate, may contain NH, Mg, Ê, and Na. Evaporate and ignite to expel NH, salts, which will have been already detected in the preliminary examination; mix the residue with mercuric oxide (Hg, O) in excess, and a drop of water; ignite, extract with boiling water, and filter whilst hot. A residue will consist of MgHO, and indicates the presence of Mg. Evaporate the filtrate to dryness, test one portion of the residue before the blowpipe for Na; dissolve the remainder in dilute HCl, and add |