Qualitative Chemical Analysis

Transcription

1 Qualitative Chemical Analysis István Szalai Institute of Chemistry, Eötvös University 2018 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

2 Topics Acid-base theories; reduction-oxidation reactions: reducing and oxidizing agents, balancing redox equations; complex equilibria; precipitation reactions, principles of solubility equilibria; factors influencing solubility equilibria Classification and reactions of ions; group reagents for qualitative analysis of cations and anions; identifications reactions for cations and anions ph calculations; solubility of precipitates; effect of ph and other complexing agents on the solubility equilibria István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

3 Schedule Major Tests during the semester: Test Paper I on 5 th of March Test Paper II on 16 th of April Final Test on 7 th of May Retakes 23 rd of April and 1 th of May István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

4 Introduction Analytical chemistry Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of these components. István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis 2018 / 1

5 Introduction Analytical chemistry & pharmaceutical industry Analytical chemistry plays an increasingly important role in the pharmaceutical industry where, aside from quality assurance, it is used in discovery of new drug candidates and in clinical applications where understanding the interactions between the drug and the patient are critical. István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

6 Introduction Analytical chemistry & pharmaceutical industry Analytical chemistry plays an increasingly important role in the pharmaceutical industry where, aside from quality assurance, it is used in discovery of new drug candidates and in clinical applications where understanding the interactions between the drug and the patient are critical. If a pharmaceutical substance may contain residues of metal elements, used as catalyst(s) or reagent(s) in the synthesis, for each of these residual elements an acceptance criterion should be set... For the determination of each of the specified elements an appropriate and validated method should be used in relation to the limit to be applied... General semi-quantitative heavy metal limit tests based on the precipitation at ph 3.5 of coloured metal sulfides are described in several publications (e.g. Ph. Eur.). (Guidline on the specifications limits for residues of metal catalyst- European Medicines Agency) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

7 Introduction Reactions Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution. The solution is treated with various reagents to test for reactions characteristic of certain ions: reactions which form insoluble products, e. g. precipitates, reactions which give a characteristic color, e. g. colored complex ions, reactions which liberate gases, e. g. ammonia, carbon-dioxide. István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

8 Introduction Reactions Specific reaction are reactions which under certain conditions make it possible to detect some ions in the presence of others by the specific change in color, the formation of characteristic precipitate etc. A reaction is selective if it reacts in a similar way with only few ions. A reaction is sensitive if just a very small amount of ion gives an easily observable change. István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

9 Introduction Sensitivity of reactions Limiting concentration: The smallest amount of ion (usually in µg) in 1 ml of solution that still gives a positive reaction in a particular test (ppm). Detection limit: The smallest amount of the ions (µg or ng) that can be detected by the method concerned. István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

10 Qualitative analysis of cations Group reagents Hydrolysis: CH 3 COONa-NaCl (ph 7 8, acid-base reactions, ppt formation) hexametilenetetramine (CH 2 ) 6 N (ph 5, acid-base reactions, ppt formation) C 6 H 12 N + 6 H 2 O 6HCHO + NH 3 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

11 Qualitative analysis of cations Group reagents Group reagents: HCl (acid-base reactions, ppt formation) Alkali hydroxides (OH ) (acid-base reactions, ppt formation, complex formation) NH 3 (acid-base reactions, ppt formation, complex formation) H 2 S (ppt formation, complex formation, redox reactions) (NH ) 2 S and (NH ) 2 S x (ppt formation, complex formation, redox reactions) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

12 Qualitative analysis of cations Group reagents Group reagents: KI (ppt formation, complex formation, redox reactions) H 2 SO (ppt formation, acid-base reactions) Zn (redox reactions) KMnO (redox reactions) I 2 sol. (I 3 ) (redox reactions, ppt formation, complex formation) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

13 Qualitative analysis of cations Classification of cations Karl Remigius FRESENIUS ( ) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

14 Qualitative analysis of cations Classification of cations Group I Cations which can be precipitated as sulfides from acidic solution (ph 2) by H 2 S; the precipitates are insoluble in (NH ) 2 S and KOH. Cu 2+, Ag +, Cd 2+, Hg 2+ 2, Hg2+, Pb 2+, Bi 3+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

15 Qualitative analysis of cations Classification of cations Group I Cations which can be precipitated as sulfides from acidic solution (ph 2) by H 2 S; the precipitates are insoluble in (NH ) 2 S and KOH. Cu 2+, Ag +, Cd 2+, Hg 2+ 2, Hg2+, Pb 2+, Bi 3+ Group II Cations which can be precipitated in acidic media with H 2 S but the sulfides of are soluble in (NH ) 2 S x and KOH with formation of thiocomplexes. As(III), As(V), Sb(III), Sb(V), Sn(II), Sn(IV) {Se(IV), V(V), Mo(VI), W(VI), Au(I,III), Pt(IV)} István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

16 Qualitative analysis of cations Classification of cations Group III Cations which can be precipitated with (NH ) 2 S in neutral or slightly alkaline solutions, but cannot be precipitated with H 2 S in acidic solutions. Ni 2+, Co 2+, Fe 2+, Fe 3+, Mn 2+, Zn 2+, Cr 3+, Al 3+ {Be 2+, TiO 2+, Tl +, Ce(III,IV), UO 2+ 2 } István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

17 Qualitative analysis of cations Classification of cations Group IV The cations of Group IV cannot be precipitated with H 2 S or (NH ) 2 S, but they form precipitate with (NH ) 2 CO 3 in neutral or slightly alkaline solutions, in the presence of NH Cl. Ca 2+, Sr 2+, Ba 2+ Group V The cations of Group V cannot be precipitated with any of above reagents. Mg 2+, Na +, K +, NH + {Li + } István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

18 Qualitative analysis of cations Sulfide precipitates 2 Ag + + S 2 precipitation dissolution Ag 2 S István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

19 Qualitative analysis of cations Sulfide precipitates 2 Ag + + S 2 precipitation dissolution K so =[Ag + ] 2 [S 2 ] Ag 2 S István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

20 Qualitative analysis of cations Sulfide precipitates 2 Ag + + S 2 precipitation dissolution K so =[Ag + ] 2 [S 2 ] Ag 2 S Common ion effect: more reactants precipitation István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

21 Qualitative analysis of cations Sulfide precipitates 2 Ag + + S 2 precipitation dissolution K so =[Ag + ] 2 [S 2 ] Ag 2 S Common ion effect: more reactants precipitation ph effect: decrease of ph dissolution [S 2 ] t = [H 2 S] + [HS ] + [S 2 ] ([H 2 S] t = 0,1 mol/dm 3 and ph = 2 [S 2 ] M) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

22 Qualitative analysis of cations Sulfide precipitates 2 Ag + + S 2 precipitation dissolution K so =[Ag + ] 2 [S 2 ] Ag 2 S Complex formation: increase of ligand conc. dissolution [Ag + ] t = [Ag + ] + [Ag(NH 3 ) + ] + [Ag(NH 3 ) + 2 ] István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

23 Qualitative analysis of cations Sulfide precipitates 2 Ag + + S 2 precipitation dissolution K so =[Ag + ] 2 [S 2 ] Ag 2 S Complex formation: increase of ligand conc. dissolution [Ag + ] t = [Ag + ] + [Ag(NH 3 ) + ] + [Ag(NH 3 ) + 2 ] Redox reactions: oxidation of sulfide ions dissolution H 2 S + 2 NO H+ 3 S + 2 NO + H 2 O (5 M HNO 3 [S 2 ] 10 5 M (! N A = )) stván Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

24 Group I cations Cation which can be precipitated as sulfides from acidic solution (ph 2) by H 2 S; the precipitates are insoluble in (NH ) 2 S and KOH. Ions E 0 /V Electronic config. Pearson Oxidation (Ion/Metal) states Cu 2+ 0,3 3d 9 borderline +2, +1, 0 Ag + 0,80 d 10 soft acid +1, 0 Cd 2+ -0,0 d 10 soft acid +2, 0 Hg 2+ 0,91 5d 10 soft acid +2, +1, 0 Hg ,80 5d 10 6s 1 soft acid +2, +1, 0 Pb 2+ -0,13 5d 10 6s 2 borderline +, +2, 0 Bi 3+ 0,23 5d 10 6s 2 borderline +5, +3, 0 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

25 Group I cations H 2 S +cc HNO 3 CuS brownish black dissolves (redox reaction) Ag 2 S black dissolves (redox reaction) PbS black dissolves (redox reaction) Bi 2 S 3 black dissolves (redox reaction) 3 CuS + 2 NO H + =3 Cu S + 2 NO + H 2 O István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

26 Group I cations H 2 S +cc HNO 3 CdS yellow dissolves, but it dissolves even if the conc. of strong acid >0.5M in acid-base reaction) CdS + 2 H + =Cd H 2 S István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

27 Group I cations H 2 S +cc HNO 3 Hg 2 S (Hg + HgS) black does not dissolve, but dissolves in Br 2 /HCl (redox+complex formation reaction) HgS black does not dissolve, but Br 2 /HCl, dissolves in Br 2 /HCl (redox+complex formation reaction) HgS + Br 2 + H 2 O=HgBr 2 + SO 2 + Br + 8 H + István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

28 Group I cations Group Ia: Ag +, Pb 2+, Hg 2+ 2 White ppt with chloride ions (HCl, NaCl... ): AgCl, PbCl 2, Hg 2 Cl 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

29 Group I cations Group Ia: Ag +, Pb 2+, Hg 2+ 2 White ppt with chloride ions (HCl, NaCl... ): AgCl, PbCl 2, Hg 2 Cl 2 AgCl NH 3 Ag(NH 3 ) + 2 NH Hg 2 Cl 3 2 HgNH2 Cl + Hg NH PbCl 3 2 no reaction István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

30 Group I cations KI +I Cu 2+ CuI + I 2 yellowish white CuI 2 (KI (s)) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

31 Group I cations KI +I Cu 2+ CuI + I 2 yellowish white CuI 2 (KI (s)) Ag + AgI yellow AgI 2 (KI (s)) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

32 Group I cations KI +I Cu 2+ CuI + I 2 yellowish white CuI 2 (KI (s)) Ag + AgI yellow AgI 2 (KI (s)) Cd 2+ CdI 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

33 Group I cations KI +I Cu 2+ CuI + I 2 yellowish white CuI 2 (KI (s)) Ag + AgI yellow AgI 2 (KI (s)) Cd 2+ CdI 2 + Hg Hg 2+ 2 Hg 2 I 2 greenish yellow HgI 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

34 Group I cations KI +I Cu 2+ CuI + I 2 yellowish white CuI 2 (KI (s)) Ag + AgI yellow AgI 2 (KI (s)) Cd 2+ CdI 2 Hg 2+ 2 Hg 2 I 2 greenish yellow HgI 2 + Hg Hg 2+ HgI 2 red HgI 2 yellow István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

35 Group I cations KI +I Cu 2+ CuI + I 2 yellowish white CuI 2 (KI (s)) Ag + AgI yellow AgI 2 (KI (s)) Cd 2+ CdI 2 Hg 2+ 2 Hg 2 I 2 greenish yellow HgI 2 + Hg Hg 2+ HgI 2 red HgI 2 yellow Pb 2+ PbI 2 yellow PbI 2 (KI (s) ) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

36 Group I cations KI +I Cu 2+ CuI + I 2 yellowish white CuI 2 (KI (s)) Ag + AgI yellow AgI 2 (KI (s)) Cd 2+ CdI 2 Hg 2+ 2 Hg 2 I 2 greenish yellow HgI 2 + Hg Hg 2+ HgI 2 red HgI 2 yellow Bi 3+ BiI 3 (BiOI) black BiI Pb 2+ PbI 2 yellow PbI 2 (KI (s) ) orange István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

37 Group I cations NaOH +OH Cu 2+ Cu(OH) 2 light blue István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

38 Group I cations NaOH +OH Cu 2+ Cu(OH) 2 light blue Ag + Ag 2 O brown István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

39 Group I cations NaOH +OH Cu 2+ Cu(OH) 2 light blue Ag + Ag 2 O brown Cd 2+ Cd(OH) 2 white István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

40 Group I cations NaOH +OH Cu 2+ Cu(OH) 2 light blue Ag + Ag 2 O brown Cd 2+ Cd(OH) 2 white Hg 2+ 2 Hg 2 O (Hg, HgO) black István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

41 Group I cations NaOH +OH Cu 2+ Cu(OH) 2 light blue Ag + Ag 2 O brown Cd 2+ Cd(OH) 2 white Hg 2+ 2 Hg 2 O (Hg, HgO) black Hg 2+ HgO yellow István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

42 Group I cations NaOH +OH Cu 2+ Cu(OH) 2 light blue Ag + Ag 2 O brown Cd 2+ Cd(OH) 2 white Hg 2+ 2 Hg 2 O (Hg, HgO) black Hg 2+ HgO yellow Pb 2+ Pb(OH) 2 white Pb(OH) 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

43 Group I cations NaOH Cu 2+ Cu(OH) 2 light blue Ag + Ag 2 O brown Cd 2+ Cd(OH) 2 white +OH Hg 2+ 2 Hg 2 O (Hg, HgO) black Hg 2+ HgO yellow Pb 2+ Pb(OH) 2 white Pb(OH) 2 Bi 3+ Bi(OH) 3 white István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

44 Group I cations NH 3 +NH 3 Cu 2+ Cu(OH) 2 Cu(NH 3 ) 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

45 Group I cations NH 3 +NH 3 Cu 2+ Cu(OH) 2 Cu(NH 3 ) 2+ Ag + Ag 2 O Ag(NH 3 ) + 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

46 Group I cations NH 3 +NH 3 Cu 2+ Cu(OH) 2 Cu(NH 3 ) 2+ Ag + Ag 2 O Ag(NH 3 ) + 2 Cd 2+ Cd(OH) 2 Cd(NH 3 ) 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

47 Group I cations NH 3 +NH 3 Cu 2+ Cu(OH) 2 Cu(NH 3 ) 2+ Ag + Ag 2 O Ag(NH 3 ) + 2 Cd 2+ Cd(OH) 2 Cd(NH 3 ) 2+ Hg 2+ 2 Hg(NH 2 )Cl + Hg István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

48 Group I cations NH 3 +NH 3 Cu 2+ Cu(OH) 2 Cu(NH 3 ) 2+ Ag + Ag 2 O Ag(NH 3 ) + 2 Cd 2+ Cd(OH) 2 Cd(NH 3 ) 2+ Hg 2+ 2 Hg(NH 2 )Cl + Hg Hg 2+ Hg(NH 2 )Cl HgO Hg(NH 2 )NO 3 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

49 Group I cations NH 3 +NH 3 Cu 2+ Cu(OH) 2 Cu(NH 3 ) 2+ Ag + Ag 2 O Ag(NH 3 ) + 2 Cd 2+ Cd(OH) 2 Cd(NH 3 ) 2+ Hg 2+ 2 Hg(NH 2 )Cl + Hg Hg 2+ Hg(NH 2 )Cl HgO Hg(NH 2 )NO 3 Pb 2+ Pb(OH) 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

50 Group I cations NH 3 +NH 3 Cu 2+ Cu(OH) 2 Cu(NH 3 ) 2+ Ag + Ag 2 O Ag(NH 3 ) + 2 Cd 2+ Cd(OH) 2 Cd(NH 3 ) 2+ Hg 2+ 2 Hg(NH 2 )Cl + Hg Hg 2+ Hg(NH 2 )Cl HgO Hg(NH 2 )NO 3 Pb 2+ Pb(OH) 2 Bi 3+ Bi(OH) 3 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

51 Group I cations Redox reactions Ion Oxidation Reduction Cu 2+ Cu2+ Fe,Zn Cu, Cu 2+ I CuI + I 2 Cu 2+ CN CuCN + (CN) 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

52 Group I cations Redox reactions Ion Oxidation Reduction Cu 2+ Cu2+ Fe,Zn Cu, Cu 2+ I CuI + I 2 Cu 2+ CN CuCN + (CN) 2 Ag + Ag + Cu Ag, Ag(NH 3 ) + 2 formaldehide Ag István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

53 Group I cations Redox reactions Ion Oxidation Reduction Cu 2+ Cu2+ Fe,Zn Cu, Cu 2+ I CuI + I 2 Cu 2+ CN CuCN + (CN) 2 Ag + Ag + Cu Ag, Ag(NH 3 ) + formaldehide 2 Ag Cd 2+ Cd2+ Zn Cd István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

54 Group I cations Redox reactions Ion Oxidation Reduction Cu 2+ Cu2+ Fe,Zn Cu, Cu 2+ I CuI + I 2 Cu 2+ CN CuCN + (CN) 2 Ag + Ag + Cu Ag, Ag(NH 3 ) + formaldehide 2 Ag Cd 2+ Cd2+ Zn Cd Hg 2+ Hg2+ Cu Hg SnCl 2 HgCl 2 Hg 2 Cl 2 SnCl 2 Hg István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

55 Group I cations Redox reactions Ion Oxidation Reduction Cu 2+ Cu2+ Fe,Zn Cu, Cu 2+ I CuI + I 2 Cu 2+ CN CuCN + (CN) 2 Ag + Ag + Cu Ag, Ag(NH 3 ) + formaldehide 2 Ag Cd 2+ Cd2+ Zn Cd Hg 2+ Hg2+ Cu Hg SnCl 2 HgCl 2 Hg 2 Cl 2 SnCl 2 Hg Hg 2+ Cl 2 Hg 2 Cl 2 2 HgCl 2 Hg 2+ 2 MnO Hg 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

56 Group I cations Redox reactions Ion Oxidation Reduction Pb 2+ Pb(OH) 2 OCl PbO 2 Pb2+ Zn Pb István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

57 Group I cations Redox reactions Ion Oxidation Reduction Pb 2+ Pb(OH) 2 OCl PbO 2 Pb2+ Zn Pb Bi 3+ OCl Bi(OH) Sn(OH) 2 3 BiO 2 OH Bi(OH) 3 Bi István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

58 Group I cations, analysis Group reagents Observation Conclusions Color blue Cu 2+ and all the colourless ions István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

59 Group I cations, analysis Group reagents Observation Conclusions Color blue Cu 2+ and all the colourless ions colorless no Cu 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

60 Group I cations, analysis Group reagents Observation Conclusions Color blue Cu 2+ and all the colourless ions colorless no Cu 2+ HCl precipitate Ag +, Pb 2+ Hg 2+ 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

61 Group I cations, analysis Group reagents Observation Conclusions Color blue Cu 2+ and all the colourless ions colorless no Cu 2+ HCl precipitate Ag +, Pb 2+ Hg heating no ppt no Ag + and Hg 2+ 2 only Pb 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

62 Group I cations, analysis Group reagents Observation Conclusions Color blue Cu 2+ and all the colourless ions colorless no Cu 2+ HCl precipitate Ag +, Pb 2+ Hg heating no ppt no Ag + and Hg 2+ 2 ppt does not dissolve Ag + and Hg 2+ 2 only Pb 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

63 Group I cations, analysis Group reagents Observation Conclusions Color blue Cu 2+ and all the colourless ions colorless no Cu 2+ HCl precipitate Ag +, Pb 2+ Hg heating no ppt no Ag + and Hg 2+ 2 only Pb 2+ ppt does not dissolve Ag + and Hg 2+ 2 Hydrolysis ppt Bi 3+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

64 Group I cations, analysis Group reagents Observation Conclusions Color blue Cu 2+ and all the colourless ions colorless no Cu 2+ HCl precipitate Ag +, Pb 2+ Hg heating no ppt no Ag + and Hg 2+ 2 only Pb 2+ ppt does not dissolve Ag + and Hg 2+ 2 Hydrolysis ppt Bi 3+ no ppt no Bi 3+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

65 Group I cations, analysis Group reagents Observation Conclusions NH 3 ppt can be Bi 3+, Pb 2+, Hg 2+ amine complexes?! István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

66 Group I cations, analysis Group reagents Observation Conclusions NH 3 ppt can be Bi 3+, Pb 2+, Hg 2+ amine complexes?! no ppt only Cu 2+, Ag +, Cd 2+ no Bi 3+, Pb 2+, Hg 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

67 Group I cations, analysis Group reagents Observation Conclusions NH 3 ppt can be Bi 3+, Pb 2+, Hg 2+ amine complexes?! no ppt only Cu 2+, Ag +, Cd 2+ no Bi 3+, Pb 2+, Hg 2+ NaOH ppt can be Cu 2+, Bi 3+, Cd 2+, Hg 2+, Ag + István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

68 Group I cations, analysis Group reagents Observation Conclusions NH 3 ppt can be Bi 3+, Pb 2+, Hg 2+ amine complexes?! no ppt only Cu 2+, Ag +, Cd 2+ no Bi 3+, Pb 2+, Hg 2+ NaOH ppt can be Cu 2+, Bi 3+, Cd 2+, Hg 2+, Ag + no ppt only Pb 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

69 Group I cations, analysis Group reagents Observation Conclusions KI colored ppt BiI 3 black, HgI 2 red complexes PbI 2 yellow, BiI orange no ppt only Cd 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

70 Group I cations, analysis Reagent, observation products Cu 2+ NH 3, blue Cu(NH 3 ) 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

71 Group I cations, analysis Reagent, observation products Cu 2+ NH 3, blue Cu(NH 3 ) 2+ Ag + HCl white ppt AgCl NH 3 Ag(NH 3 ) + 2 can be dissolved in NH 3 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

72 Group I cations, analysis Reagent, observation products Cu 2+ NH 3, blue Cu(NH 3 ) 2+ Ag + HCl white ppt AgCl NH 3 Ag(NH 3 ) + 2 can be dissolved in NH 3 Hg 2+ NH 2 HCl white ppt, +NH 3 Hg 2 Cl 3 2 HgNH2 Cl + ppt become black + Hg István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

73 Group I cations, analysis Reagent, observation products Cu 2+ NH 3, blue Cu(NH 3 ) 2+ Ag + HCl white ppt AgCl NH 3 Ag(NH 3 ) + 2 can be dissolved in NH 3 Hg 2+ NH 2 HCl white ppt, +NH 3 Hg 2 Cl 3 2 HgNH2 Cl + ppt become black + Hg SnCl 2 SnCl 2 white ppt, Hg 2 Cl 2 Hg in excess gray I KI red ppt, that HgI 2 HgI 2 dissolves in excess Hg 2+ István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

74 Group I cations, analysis Reagent, observation products Pb 2+ H 2 SO white ppt PbSO KI yellow ppt. PbI 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

75 Group I cations, analysis Reagent, observation products Pb 2+ H 2 SO white ppt PbSO KI yellow ppt. PbI 2 Bi 3+ KI black ppt., in excess BiI 3 I BiI orange solution Sn(OH) 2 Sn(OH) 2 black ppt Bi(OH) 3 Bi hidrolysis, white ppt BiOCl István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

76 Group I cations, analysis Reagent, observation products Pb 2+ H 2 SO white ppt PbSO KI yellow ppt. PbI 2 Bi 3+ KI black ppt., in excess BiI 3 I BiI orange solution Sn(OH) 2 Sn(OH) 2 black ppt Bi(OH) 3 Bi hidrolysis, white ppt BiOCl Cd 2+ (a) heating with Fe powder CdS filtrate +HCl+H 2 S yellow ppt (b) NH 3, filtration + CN +(NH ) 2 S yellow ppt István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

77 Group I cations, analysis Cd 2+ and Cu 2+ in presence of each other 1 NH 3 [Cu(NH 3 ) ] 2+ and [Cd(NH 3 ) ] 2+ 2 KCN [Cu(CN) ] 3 and [Cd(CN) ] 2 3 (NH ) 2 S CdS István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

78 Group I cations, analysis Cd 2+ and Cu 2+ in presence of each other 1 NH 3 [Cu(NH 3 ) ] 2+ and [Cd(NH 3 ) ] 2+ 2 KCN [Cu(CN) ] 3 and [Cd(CN) ] 2 3 (NH ) 2 S CdS 1 iron powder Cu and Cd 2+ 2 H 2 S CdS István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

79 Group I cations, analysis Hg 2+ and Bi 3+ in presence of each other 1 CH 3 COONa-NaCl or hexametilenetetramine Hg 2+, BiOCl 2 filtration 3 ppt + HOCl BiO 2 (OH) solution + SnCl 2 Hg 2 Cl 2 + SnCl 2 Hg István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

80 Group II cations The cations of Group II can be precipitated in acidic media with H 2 S but the sulfides of are soluble in (NH ) 2 S x and KOH with formation of thiocomplexes. Ion Elektronic config. Pearson Oxidation number As(III) 3d 10 s 2 hard acid +5, +3, 0, (-3) H 3 AsO 3, AsO 3 3 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

81 Group II cations The cations of Group II can be precipitated in acidic media with H 2 S but the sulfides of are soluble in (NH ) 2 S x and KOH with formation of thiocomplexes. Ion Elektronic config. Pearson Oxidation number As(III) 3d 10 s 2 hard acid +5, +3, 0, (-3) H 3 AsO 3, AsO 3 3 As(V) 3d 10 hard acid H 3 AsO, AsO 3 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

82 Group II cations Ion Elektronic config. Pearson Oxidation number Sb(III) d 10 s 2 borderline +5, +3, 0, (-3) SbCl István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

83 Group II cations Ion Elektronic config. Pearson Oxidation number Sb(III) d 10 s 2 borderline +5, +3, 0, (-3) SbCl Sb(V) d 10 hard acid SbCl 6 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

84 Group II cations Ion Elektronic config. Pearson Oxidation number Sb(III) d 10 s 2 borderline +5, +3, 0, (-3) SbCl Sb(V) d 10 hard acid SbCl 6 Sn(II) d 10 s 2 borderline +, +2, 0, (-) SnCl 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

85 Group II cations Ion Elektronic config. Pearson Oxidation number Sb(III) d 10 s 2 borderline +5, +3, 0, (-3) SbCl Sb(V) d 10 hard acid SbCl 6 Sn(II) d 10 s 2 borderline +, +2, 0, (-) SnCl 2 Sn(IV) d 10 hard acid SnCl6 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

86 Group II cations Sulfide precipitates (NH ) 2S (NH ) 2S x KOH cc HCl As(V) As 2S 3+ S AsS 3 3 AsS 3 AsO AsS3 3 (As 2S 5) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

87 Group II cations Sulfide precipitates (NH ) 2S (NH ) 2S x KOH cc HCl As(V) As 2S 3+ S AsS 3 3 AsS 3 AsO AsS3 3 (As 2S 5) As(III) As 2S 3 AsS 3 3 AsS 3 AsO AsS3 3 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

88 Group II cations Sulfide precipitates (NH ) 2S (NH ) 2S x KOH cc HCl As(V) As 2S 3+ S AsS 3 3 AsS 3 AsO AsS3 3 (As 2S 5) As(III) As 2S 3 AsS 3 3 AsS 3 AsO AsS3 3 Sb(V) Sb 2S 3+ S SbS 3 3 SbS 3 Sb 2S 5 Sb(OH) + SbS3 3 Sb(OH) 6 Sb(Cl) Sb(Cl) 6 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

89 Group II cations Sulfide precipitates (NH ) 2S (NH ) 2S x KOH cc HCl As(V) As 2S 3+ S AsS 3 3 AsS 3 AsO AsS3 3 (As 2S 5) As(III) As 2S 3 AsS 3 3 AsS 3 AsO AsS3 3 Sb(V) Sb 2S 3+ S SbS 3 3 SbS 3 Sb(OH) + SbS3 3 Sb(Cl) Sb 2S 5 Sb(OH) 6 Sb(Cl) 6 Sb(III) Sb 2S 3 SbS 3 3 SbS 3 Sb(OH) + SbS3 3 Sb(Cl) István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

90 Group II cations Sulfide precipitates (NH ) 2S (NH ) 2S x KOH cc HCl As(V) As 2S 3+ S AsS 3 3 AsS 3 AsO AsS3 3 (As 2S 5) As(III) As 2S 3 AsS 3 3 AsS 3 AsO AsS3 3 Sb(V) Sb 2S 3+ S SbS 3 3 SbS 3 Sb(OH) + SbS3 3 Sb(Cl) Sb 2S 5 Sb(OH) 6 Sb(Cl) 6 Sb(III) Sb 2S 3 SbS 3 3 SbS 3 Sb(OH) + SbS3 3 Sb(Cl) Sn(IV) SnS 2 SnS 2 3 SnS 2 3 Sn(OH) S2 Sn(Cl) 2 6 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1

91 Group II cations Sulfide precipitates (NH ) 2S (NH ) 2S x KOH cc HCl As(V) As 2S 3+ S AsS 3 3 AsS 3 AsO AsS3 3 (As 2S 5) As(III) As 2S 3 AsS 3 3 AsS 3 AsO AsS3 3 Sb(V) Sb 2S 3+ S SbS 3 3 SbS 3 Sb(OH) + SbS3 3 Sb(Cl) Sb 2S 5 Sb(OH) 6 Sb(Cl) 6 Sb(III) Sb 2S 3 SbS 3 3 SbS 3 Sb(OH) + SbS3 3 Sb(Cl) Sn(IV) SnS 2 SnS 2 3 SnS 2 3 Sn(OH) S2 Sn(Cl) 2 6 Sn(II) SnS SnS 2 3 Sn(OH) 2 + S 2 Sn(Cl) 2 István Szalai (Institute of Chemistry, Eötvös University) Qualitative Chemical Analysis / 1