Qualitative and quantitative chemical analysis

dr. S. H. Burungale

1. Qualitative and quantitative Chemical analysis Dr. S.H. Burungale Department of Chemistry Yashwantrao Chavan College of Science Karad

2. What is Analytical Chemistry?  Application of a process or series of processes in order to indentify and/or quantify a substance, the components of a solution or mixture, or the determination of the structure of chemical compounds

3. Types on basis of analyte size Macro Analysis -0.1g Meso ( Semimicro ) Analysis -0.01 to 0.1g Micro Analysis -0.001g to 0.01g Submicro Analysis -0.0001g to 0.001g Ultromicro Analysis -0.0001g 

4. Classification of Analytical Chemistry  Qualitative Analysis . It gives information about atomic and molecular species or the functional group in sample.  Mp,bp,specific gravity, RI,Absorbance,Optical rotation, Viscosity, particle size,etc . Quantitative Analysis . It gives relative amount of one or more of the analyte in numerical terms. 

5. Analytical Methods  Chemical Methods Physico -chemical Methods Microbiological Methods Biological Methods Chemical Methods : Volumetric Neutralization titrations, Non-aqueous Precipitation Redox Complexometric Gravimetric Gasometrical 

6. Physico -chemical Methods Instruments Methods Physical Properties 1.Potentimeter Electrical Potential 2.Conductometer Conductance 3 Polarography Voltametry Current 4 Spectrophotometry , Colorimetry AAS Absorption of radiation 5 Emission Spectroscopy , flame photometry fluorometry Emission of radiation 6 Turbidometry Nephalometry Scattering of radiation 7 Refractometry Refraction of radiation 8 Polarimetry, ORD Rotation of Plane polarized light 9 Thermal methods Thermal properties 10 Mass spectrophotometer Mass to charge ratio

7. CATION GROUPS AND REAGENTS Group Group Reagent Cations (some metals as more stable oxy anions) Group I Dil. HCl (2M) Hg + , Ag + , Pb + , Group II Dil. HCl + H2S gas Hg2+, Pb2+, Bi3+, Cu2+, Cd2+ . As3+, Sb3+, Sn2+, Sn4+, SeO3 2- , SeO4 2- , TeO3 2- , TeO4 2- , MoO4 2- Group III A NH4Cl + NH4OH solutions (2M) Al3+, Cr3+, Fe2+ , Fe3+, Ce4+, Th4+, Ti4+, ZrO2+, VO3 2- , UO2 2+ Group III B NH4Cl + NH4OH+ H2S gas Co2+, Ni2+, Mn2+, Zn2+ Group IV NH4Cl + NH4OH + (NH4)2CO3 solutions (2M) Ca2+, Sr2+, Ba2+ Group V NH4OH + (NH4)2HPO4 or Na2HPO4 Mg2+ Other Radicals No common reagent NH4 + , Na+ ,Li+ , K +

8. Group I 2 cm3 of dilute HCl Boil residue in the centrifuge tube Residue: White – Hg2Cl2 or AgCl . Yellow - H2WO4 . Centrifugate Pb2+or Tl + Boil the residue with 5 cm 3 of dilute NH3 solution and centrifuge. Residue: Centrifugate: Black precipitate, Hg(NH2) Cl and Hg. [Ag(NH3)2] + or H2WO4 . Dissolve the residue by heating with 2 cm3 of aqua regia , cool dilute HCl , dilute NH3. KI, Residue: Pale yellow precipitate of AgI . Centrifugate: Tungstic acid (H2WO4) solution. 1 cm3 of conc. H2SO4 Residue: White – PbSO4 . Centrifugate Add dilute NH3 solution and boil off excess NH3 . To 1 cm3, acetic acid and K2CrO4 yellow precipitate of Tl2CrO4

9. Hg(I) Spot test: 1.Place a drop of faintly acid test solution (original) on a drop reaction paper and add a drop of saturated potassium nitrite (KNO2) solution. A black spot of Hg is produced. 2.To 1 cm3 of the solution, add K2CrO4 solution and heat. A brown precipitate changing to red Hg2CrO4 on heating Spot test Ag(I) Spot test: Place a drop of the test solution (original) on a watch glass and add a drop of ammonium carbonate solution and mix. Withdraw a drop of clear liquid from the mixture and place it on a drop reaction paper and add a drop of K2CrO4 solution. A red ring is obtained due to formation of Ag2CrO4 .

10. Residue: White – PbSO4 . Dissolve in ammonium acetate solution (or a mixture of NH3 solution and acetic acid) and the following tests are done: To 1 cm3 of the solution, add acetic acid and K2CrO4 solution. A yellow precipitate of PbCrO4 is formed 2) To 1 cm3 of the solution, add KI solution. Boil and cool. A yellow precipitate of PbI2 is formed, which dissolves on heating and re-precipitates as golden spangles on cooling. 3) Spot test: Place a drop of the solution on a drop reaction paper and add a drop of ammonium sulphide solution. A black spot of PbS is formed.

11. Centrifugate: May contain Tl + . Add dilute NH3 solution and boil off excess NH3 . Cool and do the following tests: 1) To 1 cm3 of the solution, add acetic acid and K2CrO4 solution. A yellow precipitate of Tl2CrO4 is formed. 2) Spot test: Place a drop of the solution on a drop reaction paper and add a drop sodium thiosulphate solution. Add a drop of KI solution over it. A yellow spot of Tl (I) is produced.

12. Group II Wash the Group II residue with 2 cm3 of a solution of ammonium chloride saturated with H2S and centrifuge. Discard centrifugate . Transfer residue into a small beaker and add 5 cm3 of yellow ammonium sulphide ( amm . polysulphide ) solution. Heat to about 50 to 600C and maintain at this temperature for 5 minutes with stirring. If there is a precipitate, cool and centrifuge. Residue: Black HgS , PbS , Bi2S3 or CuS . Yellow – CdS Centrifugate: Add conc. HCl dropwise till just acidic (do not add excess!) and warm while stirring. A fine white or pale yellow precipitate is only sulfur. If a flocculant precipitate is formed, centrifuge . Residue: Yellow – SnS2, Se or As2S3. Orange red – Sb2S3. Brown -Te, SnS or MoS3. Group IIA Group IIB

13. Group IIA residue is washed two times using 2 cm3 of distilled water and centrifuged. Discard washings. Transfer residue to a small beaker, add 10 cm3 of dilute nitric acid and boil for 5 minutes. If some solid material remains, cool and centrifuge . Residue: Black – HgS . Centrifugate : May contain nitrate of Pb , Bi, Cu or Cd . Add dilute H2SO4 till precipitation Residue: White – PbSO4 Centrifugate Bi, Cu or Cd . Add concentrated NH3 If a residue remains, centrifuge. Residue: White – Bi(OH)2 . Centrifugate Cu or Cd Add dilute acetic acid with shaking till a clear solution is obtained. Divide into two parts.

14. Group IIB Residue into a small conical flask and place a funnel in its mouth. Add 5 cm3 of conc. HCl and boil gently for 5 minutes. Dilute with 3 cm3 of distilled water, cool and centrifuge. Residue: Yellow - Se or As2S3 . Brown –Te or MoS3 . HCl +potassium chlorate (KClO3 concentrate by evaporating on a water bath. Cool and add NH3 solution with stirring till smell of ammonia persists. Add 2 cm3 of Mg(NO3 )2 solution and stir for 5 minutes. When precipitation is complete, centrifuge. Centrifugate: May contain Sb or Sn as chloride. Boil to expel H2S. Cool and carry out the following tests using small portions of the solution Residue: White crystalline Mg(NH4 )AsO4 .6H2O Centrifugate: May contain Se, Te or Mo as chlorides

15. Centrifugate: May contain Se, Te or Mo as chlorides. Transfer to a small beaker and boil off NH3 . Add 2 cm3 of conc. HCl and evaporate to half volume on a water bath. Add 2 cm3 of a saturated solution of sodium sulphite (Na2SO3 ) solution. If a precipitate is formed, centrifuge Residue: Red – Se. Dissolve the residue by heating with 1 cm3 of conc. HNO3 . Neutralise by adding amm . carbonate solution dropwise till effervescence stops Centrifugate: Dilute with equal volume of water. Add 1 cm3 of KI solution and a drop of sodium sulphite (Na2SO3 ) solution. If a precipitate is formed, centrifuge Residue: Black – Te Dissolve in 2 cm3 of cold dilute HCl . Divide the solution into three parts. Centrifugate: Add 1 cm3 of conc. HCl and boil to remove dissolved SO2 Mo (VI) Black – Te Red – Se

16. Group II B Centrifugate: May contain Sb or Sn as chloride. Boil to expel H2S. Cool and carry out the following tests using small portions of the solution. To 2 cm3 of the solution in a test tube, add a pinch of iron filings and boil to reduce Sn (IV) to Sn (II). Cool and centrifuge. With draw the clear supernatant carry out the following tests To 1 cm3 of the solution in a test tube, add just enough NH3 solution to neutralize. (A slight precipitation may occur ). Add a pinch of solid oxalic acid and boil. Pass H2S through the solution. An orange precipitate of Sb2S3 is obtained to 1 cm3 of the solution in a test tube, add two drops of mercuric chloride (HgCl2 ) solution. A silky white or grey precipitate of Hg2Cl2 is obtained. To 0.5 cm3 of the solution in a test tube, add NaOH solution dropwise with shaking. A white precipitate of Sn (OH)2 soluble in excess NaOH is obtained.

17. Presence of As is confirmed by Spot test: To the third portion, add two drops of conc. H2O2 solution and warm. Acidify with a few drops of acetic acid. Place a drop of this mixture on a drop reaction paper followed by a drop of AgNO3 solution. A red spot is obtained. Presence of Se (IV) is confirmed . To one part, add BaCl2 solution. A white precipitate of BaSeO3 is formed. To the second part, add CuSO4 solution. A bluish green precipitate of CuSeO3 is formed.

18. Neutralise one portion by adding amm . carbonate solution dropwise till effervescence stops. Add BaCl2 solution. A white precipitate of BaTeO3 is formed. To the second part, add excess of KI solution. A red colour is produced due to formation of [TeI6 ] 2- . Presence of Te (IV) is confirmed. Presence of Mo (VI) is confirmed. To one part, add pot.ferrocyanide solution. A reddish brown precipitate of Mo ferrocyanide is formed. To the second part, add two drops of ferroussulphate solution. A blue colour is produced . 3) Spot test: Place a drop of the third portion on a drop reaction paper and add a drop of pot. Thiocyanate solution. Then add a drop of SnCl2 solution. A red spot of [Mo(SCN)6 ] 3- is seen

19. Presence of Sn is confirmed. to 1 cm3 of the solution in a test tube, add two drops of mercuric chloride (HgCl2 ) solution. A silky white or grey precipitate of Hg2Cl2 is obtained. To 0.5 cm3 of the solution in a test tube, add NaOH solution dropwise with shaking. A white precipitate of Sn (OH)2 soluble in excess NaOH is obtained . Presence of Sb is confirmed. Spot test: Place a drop of the solution on a spot plate and add a minute crystal of sodium nitrite (NaNO2 ) . Then add a drop of rhodamine - B reagent. A blue colour is obtained

20. Group-III A (Iron Group) residue is washed with 2% amm . nitrite (NH4NO2) solution and dissolved in the minimum quantity of dilute HCl . Prepare a mixture containing 2 cm3 of 30% H2O2 solution and a fresh pellet of NaOH dissolved in 2 cm3 of water. Add the weakly acidic test solution into it and boil for 5 minutes. Centrifuge. Residue: White – TiO2.xH2O or ZrO2.xH2O or ThO2.xH2O or MnO2.xH2O; Brown – Fe(OH)3; Yellow – CeO3.xH2O.Wash the residue with hot 2% amm . nitrite (NH4NO2) solution Dissolve by boiling with 5 cm3 of dilute HCl and do the following tests as Centrifugate: May contain CrO4 2- , [Al(OH)4] - , VO3 - or U2O7 2- . Transfer to a small beaker and acidify with 2 cm3 of conc. HNO3 and dilute with 5cm3 of water. Boil and concentrate to half volume. Add 2 cm3 of lead nitrate solution and a pinch of solid amm . acetate. Boil and centrifuge.

21. Residue: White – TiO2.xH2O or ZrO2.xH2O or ThO2.xH2O or MnO2.xH2O; Brown – Fe(OH)3; Yellow – CeO3.xH2O.Wash the residue with hot 2% amm . nitrite (NH4NO2) solution). Dissolve by boiling with 5 cm3 of dilute HCl and do the following tests as appropriate Spot test: Place a drop of the solution on a drop reaction paper. Add a drop of pot. Ferrocyanide solution. A blue spot of ferric ferrocyanide indicates Fe 2) To 1 cm3 of the solution, add a few drops of H2O2 solution. Orange colour indicates Ti. White precipitate indicates Zr . Spot test: Place a drop of solution on a drop reaction paper. Add a drop of catechol solution. A yellow or orange spot indicates Ti. Spot test: Place a drop of solution on a spot plate. Add a drop of Alizarin-S solution and a drop of conc.HCl . A red precipitate indicates Zr 3) To 1 cm3 of the solution, add a few drops of saturated oxalic acid solution. White precipitate indicates Th or Ce. Centrifuge and discard supernatant. Boil residue with 5 cm3 of saturated amm . oxalate solution. If there is a residue,centrifuge Residue: Ce(III)oxalate. Boil residue with 2 cm3 of NaOH solution. A yellow precipitate of Ce(OH)4 is obtained. Centrifugate : Acidify 1 cm3 of the solution with dilute HCl . Thoriumoxalate is re-precipitated 1) To 0.5 cm3 of the solution, add a drop of pot. (or amm .) thiocyanate (KCNS) solution. Red colour of FeCNS indicates Fe(III)

22. 4) To 1 cm3 of the solution, add a few drops of conc. H2SO4 and evaporate till fumes. Cool, dilute and add two drops of conc. HNO3 and a pinch of PbO2. Boil and allow to stand. Purple supernatant (MnO4 - ) indicates Mn . If Mn is indicated, add excess of NH3 solution into the remaining solution and pass H2S gas. A pink precipitate of MnS . Confirm: Mn (II) Spot test: Place a drop of the aqueous layer on a spot plate and add a drop of CuSO4 solution. A green ( metavanadate ) or yellow ( pyrovanadate ) precipitate. Confirm : V (IV)

23. Centrifugate: Group III A May contain CrO4 2- , [Al(OH)4] - , VO3 - or U2O7 2- . Add 2 cm3 of conc. HNO3 and water. Boil and concentrate ,Add 2 cm3 of lead nitrate and a pinch of solid amm . acetate. Boil and centrifuge. Residue: Yellow – PbCrO4 or Pb (VO3)2 Centrifugate: May contain Al3+ , UO2 2+ Wash the precipitate with 2 cm3 of water and combine the centrifugates . Boil to expel all the H2S and concentrate. Neutralise with NH3 solution and add 5 cm3 of amm . carbonate solution. Boil for 5minutes. Cool and centrifuge Residue: White – Al(OH)3. Centrifugate: [UO2(CO3)3] 4- .

24. Spot test: Place a drop of the solution on a drop reaction paper. Add a drop of pot. Ferrocyanide solution. A blue spot of ferric ferrocyanide indicates Fe. Presence of Fe is confirmed. Spot test: Place a drop of solution on a drop reaction paper. Add a drop of catechol solution. A yellow or orange spot indicates Ti. Presence of Ti (IV) is confirmed . Spot test: Place a drop of solution on a spot plate. Add a drop of Alizarin-S solution and a drop of conc.HCl . A red precipitate indicates Zr . Presence of Zr (IV) is confirmed .

25. Spot test: A yellow precipitate of Ce(OH)4 a little of the above precipitate and dissolve it in two drops of conc.HNO3. Place a drop of solution on a spot plate and add a drop of a 5% alcoholic solution of anthranilic acid. A blackish blue precipitate rapidly changing to a brown solution. Presence of Ce(IV) is confirmed. Spot test: Thoriumoxalate is re-precipitated a little of the above precipitate and dissolve it in two drops of conc. HNO3. Place a drop of solution on a spot plate and add a drop of pot. Ferrocyanide solution. A white precipitate of thorium ferrocyanide is formed. Presence of Th (IV) is confirmed.

26. Spot test: Place a drop of the amyl alcohol layer on a spot reaction paper and evaporate off the alcohol by warming .Place a drop of diphenyl carbazide reagent on it. A blueviolet colour is seen. Presence of Cr(III) is confirmed . Spot test: Place adrop of the solution on a spot plate and add a drop of Alizarin-S reagent .Add drops of acetic acid till violet colourd is appears. A red precipitate. Presence of Al(III) is confirmed.

27. Group III B NH3, NH4Cl and H2S Residue CoS (black), NiS (black), Centrifugate: Mn2+ or Zn2+ Dissolve in 4 cm3 of aqua regia and transfer to a china dish. Evaporate carefully by heating over a wire gauze to dryness Blue residue: Co2+ . Yellow residue: Indicates Ni2+ . Boil down to half volume to remove all H2S. Add 2 cm3 of NaOH solution and two drops of conc. H2O2 solution. Boil for 2 minutes and if there is a residue, centrifuge Residue: Dark brown MnO2.xH2O Centrifugate: Na2ZnO2.

28. Separation of co2+ andNi2+ Cobalt and nickel sulphides are soluble in aqua regia .cobalt and Nickel chloride are form soluble complexes with a KCN 3CoS+6HCl +2HNO3 3CoCl2 +2NO+3S+ 4H2O 3NiS +6HCl +2HNO3 3NiCl2 +2NO+3S+ 4H2O CoCl2 +2KCN Co(CN)2 +2KCL Co(CN)2 +4KCN k4 [Co(CN)6+ NaOH+Br2 k3 [Co(CN)6 NiCl2 +2KCN NI(CN)2 +2KCL Ni(CN)2 +4KCN k4 [Ni(CN)6 Ni2O3 +4NaCN+4KCN+2H2O CoCl2 +2KNO2 Co(NO2)2 +2KCL KNO2+CH3COOH CH3OOK +HNO2 Co(NO2)2 +3KNO2 + 2HNO2 K3Co(CN)6] +NO +H2O

29. Spot test: Place a drop of the solution on a spot plate and two drops of amm . (or pot.) thiocyanate solution. A blue colour appears due to the formation of [Co(SCN)4] 2- . Presence of Co2+ is confirmed Spot test: Place a drop of the solution on a spot plate. Add one drop each of dimethylglyoxime reagent and NH3 solution. A red colour or precipitate of nickel dimethyl glyoxime complex is formed. Presence of Ni(II) is confirmed.

30. Spot test: Place a drop of the solution on a spot plate. Add one drop of conc. HNO3 and a small crystal of solid sodium bismuthate . A purple colour is produced due to formation of permanganate ions. Presence of Mn (II) is confirmed. Spot test: Place a drop of the above solution on a spot plate. Add one drop each of CuSO4 solution and amm . Mercurothiocyanate reagent. A violet precipitate consisting of the mixed mercurothiocyanates of Cu and Zn is formed. Presence of Zn(II) is confirmed

31. Group IV NH4Cl + NH4OH + (NH4)2CO3 solutions (2M) PPT of of Ca Sr , Ba Carbonates 5 cm3 of dilute acetic acid +Potassium Chromate and Boil. Residue: Yellow - BaCrO4. Centrifugate Sr , Ca. saturated amm . Sulphate + 0.5M sodium thiosulphate Residue: White – SrSO4. Centrifugate Ca

32. Spot test: Place a drop of the second part on a drop reaction paper and add a drop of sodium rhodizonate reagent. A red stain is produced due to the formation of barium rhodizonate . Presence of Ba (II) is confirmed. Spot test: Place a drop of the second part on a drop reaction paper and add a drop of sodium rhodizonate reagent. A reddish brown stain is produced due to the formation of strontium rhodizonate . Presence of Sr (II) is confirmed . Spot test: Extract the remaining residue with 1 cm3 of dilute acetic acid. Place a drop of it on a spot plate and add two drops of picrolinic acid reagent. A white precipitate of calcium picrolinate is produced. Presence of Ca(II) is confirmed.

33. Group V Mg2+ NH4OH + (NH4)2HPO4 or Na2HPO4 Dissolve the Ppt in 2 cm3 of dilute HCl . The Solution is used as follows For magnesium 1) Two drops of the solution in a test tube + 4N NH4OH, and then NH3 solution drop wise till smell persists. Add 1 cm3 3% Oxine reagent in CHCl3.Shake well and centrifuge – Yellowish Green layer 2) Two drops of solution in a test tube + 0.5cm3 of 10% NaOH + 2-3 drops of 0.1% Titan Yellow Reagent ,Centrifuge it – Red Ppt or Colour. 3) Two drops of solution in a test tube + 2 drops of 1N NaOH Solution + 2 drops of 0.001 % p-nitrobenzene azo resorcinol ( Magneson -I) reagent – A blue colour or precipitate is obtained (which is different from the violet colour of the reagent). This is due to adsorption of the dye on the precipitated Mg(OH)2. 4) 2 drops of solution + 3-4 drops of freshly prepared hypo iodide reagent – reddish brown Ppt. Presence of Mg(II) is confirmed.

34. identification of inorganic cations Group I (Lead, Mercury Silver) Lead -

35. Quantitative Chemical Analysis Aluminum (Al) : Gravimetric Estimation : Aluminum as Oxinate 8-hydroxyquinoline Redox Titration: Complexometric titration Colorimetric method

36. CHEMICALS AND APPARATUS 1. Water sample, dominion 2. Standard 0.01M Ethylenediamminetetraacetic acid( EDTA) 3. Standard 0.01M zinc sulphate solution 4. 0.5% (wt/vol.) Erichrome Black T 5. Dilute ammonia solution 6. Distilled water 7. 25ml pipette 8. Burette 9. Funnel 10. Heating plate PROCEDURE 1. 25ml of the unknown sample was pipetted into a 250ml conical flask. 2. 30ml 0.01M EDTA was then added. 3. To ensure complete complexation of the aluminum, the resultant solution was boiled for a few minutes. 4. The solution then cooled to room temperature. 5. To ensure a suitable pH range, 1ml NH3 was added. 6. About 5 drops of Erichrome black T (EBT) indicator was then added. 7. 0.01M ZnSO4 in the burette was titrated against the excess EDTA solution until the end point is reached and the volume of ZnSO4 that reacted is recorded. 8. Step 7 was repeated twice more to obtain two other titre value and the average titre calculated.  Total Moles EDTA = No moles Zn2+ [EDTA] + No moles Al3+ [EDTA]

37. Gravimetric Determination of Aluminum as Oxinate (1) Aluminum forms an oxine complex that can be quantitatively precipitated from aqueous solution between pH 4.2-9.8; it can thus be precipitated from an acetic acid - acetate buffer solution or from an ammonia cal solution. (2) The precipitate is crystalline, easily filtered and can be readily dried between 102 - 120°C. (3) Precipitation from an acetic acid - acetate buffer solution serves to separate aluminum from beryllium, barium, calcium, strontium, and magnesium which are often associated with aluminum . Disadvantages (1) Oxine is not a highly selective reagent and if aluminum is to be precipitated from an acetic acid - acetate buffer solution, all metals except the alkalis, alkaline earths and magnesium must be absent. (2) The precipitate tends to retain the reagent leading to high results. However the method is sufficiently satisfactory for almost all practical purposes. (3) It is  carcinogenic .

38. Gravimetric estimation : Weigh accurately about 0.3 g of potassium alum in a 400-ml beaker, dissolve it in 150 ml   of DW containing 1.0 ml of 0.1 N HCl and warm the contents of the beaker to about 60°C. Add the requisite quantity of the oxine reagent and then add a 2 N solution of ammonium acetate gradually from a pipette till precipitation just commences. Add a further portion (50 ml) of ammonium acetate solution with vigorous stirring. Allow the contents of the beaker to stand for 60 minutes with frequent stirring. Filter the precipitate through No : 3 or 4 sintered glass crucible that has been previously dried to a constant weight at 130—150°C. Wash the precipitate throughly with cold DW and dry at 130 to 150°C to constant weight. Each gram of aluminium oxinate is equivalent to 0.05873 g of Al.

39. Determination of Aluminium by colorimetric Method Principle : Oxine It is a chelating agent with Al at pH 4-5 which is sparingly soluble in water but readily dissolves in chloroform The yellow complex of aluminium Oxine is determine by spectrophotometrically at 400 nm Reagent : 1% Oxine Standard Al solution 1mg/ml ( 17.59g Potash alum per litre . Procedure: To a solution containing a 60 micro gram of Al +2ml 5%EDTA + 1ml 3% Hydrogen peroxide adjust the pH 9 with ammonia add sodium thiosulphate and KCN Heat the solution at 70 to 80 0C Transfer the solution in to a Separating funnel and extract with two portion of Chloroform , wash with water and to make the volume with chloroform . Measure the absorbance at 400nm.

40. Al as potassium trioxalatoaluminate trihydrate . Theory : The purity of the complex can be determined in terms of the oxalate ions. When the complex is dissolved in dilute sulphuric acid, oxalic acid is produced which can be titrated with standard potassium permanganate solution Dissolution of the complex : Weigh accurately about 0.3 g of the complex on a watch glass. Transfer it in a 100 ml. beaker. Add to it 20 ml 2N H2SO4 (table reagent). Heat it till the complex dissolves completely. Cool it and dilute it to exactly 100 ml. in volumetric flask with distilled water Procedure : Weigh accurately about 0.3 g of the complex on a watch glass. Transfer it in a 100 ml. beaker. Add to it 20 ml 2N H2SO4 (table reagent). Heat it till the complex dissolves completely. Cool it and dilute it to exactly 100 ml. in volumetric flask with distilled water. 1000 ml 1N KMnO 4 = 27g. Al

41. DETERMINATION OF ALUMINIUM BY ICP-MS PRINCIPLE OF THE METHOD Solutions with aluminium compounds are nebulised into an argon plasma, where all components are vaporised . The ions produced are entrained in the plasma gas and introduced into a mass spectrometer, sorted according to their mass-to-charge ratios, and quantified with a channel electron multiplier. Aluminium is determined at mass 27 amu . This determination may be carried out on digest 2.3 (microwave digestion HNO3 - H2O2 - HF), digest 2.4 (digestion with HNO3 - H2O2 - HF) and digest 2.7 (digestion by dry- ashing followed by treatment with HF)

42. APPARATUS Inductively coupled plasma mass spectrometer. REAGENTS Stock Solution, Al concentration 1000 mg/L - Merck nr 1.19770. Stock Solution, Al concentration 1000 mg/L - Dissolve 17.5760 g potassium aluminium sulphate dodecahydrate , KAl (SO4)2.12H2O, in a volumetric flask of 1000 mL. Make up to 1000 mL with ultra pure water. Standard Solution, Al concentration 20 mg/L - Pipette 1 mL concentrated nitric acid (65 % s.p .) in a 100-mL polythene volumetric flask which already contains about 50 mL ultra pure water. Add 2.00 mL stock solution (and make up to volume with ultra pure water. KAl (SO4).12H2O may lose crystal water on standing. The reagent should be standardised by adding an excess of EDTA with ZnSO4 and back-titration with Eriochrome Black T as an indicator

43. CALIBRATION AND STANDARDS Standard Series - pipette 0 – 1.00 – 2.00 – 5.00 mL of the standard solution (6.2) in a 100-mL polythene volumetric flasks which already contain 40 mL ultra pure water. Add either 1.0 mL concentrated nitric acid (65 %) (digestion 2.3), 0.3 mL concentrated nitric acid (65 %) (digestion 2.4) or 0.1 mL concentrated hydrochloric acid (36 %) (digestion 2.7). Let cool down and make up to the mark with ultra pure water. This standard series has Al concentrations of 0 – 200 – 400 – 1000 µg/L. 7.2 Calibration Curve - The counts per second are plot versus Pg/L aluminium in the standard series.

44. PROCEDURE Measurement – Dilute the blanks and the sample digests 1 + 9 (v/v) with ultra pure water and mix. Measure in the standard series, the blanks and the sample digests the Al concentration with the ICP-MS at a mass of 27 amu . Make use of corrections if necessary. Remarks: A data management system and system controller are used. In this way the measurements are checked continuously and the data output is in concentration units in the digests. . Due to the linearity of the ICP-MS it is possible to calibrate the ICP-MS only with the highest and zero standard of the standard series. As a check all standards can be measured as samples .

45. Methods for Iron (Fe) Gravimetric Estimation : iron is estimated by ammonium chloride and Ammonium hydroxide as precipitating reagents. Redox Titration: titration with known concentration of Potassium dichromate by using internal or external indicatiors in presence of stanous chloride and mercuric chloride Potentiometric titration : Ferric ion titrated with known concentration of Potassium dichromate , by using a saturated calomel electrode and platinum electrode in presene of quinehydrone electrode Colorimetric method : iron estimated by using ammonium thiocyanate and sulphosalicylic acid at at wavelength.

46. Gravimetric Estimation of Iron Solid Ammonium chloride

47. Volumetric Titration of Iron (Redox Titration ) 10 mL pipet , transfer exactly 10.00 mL of an unknown solution into an Erlenmeyer flask Using a graduated cylinder, add 10 mL of 1 M H 2 SO 4  to the flask.  Fill your buret with the  KMnO 4  solution  Titrate the iron solution in the flask. The pinkish color produced by the first drop of excess  KMnO 4  signals the end point for the titration. Obtain the final volume reading from the calibration scale on the buret .

48. Potentiometric titration Theory: This experiment involves the determination of the percentage of ferrous iron in an unknown samplemixture by redox titration with potassium dichromate solution as the standard using: ( i ) ferroin indicator (ii) potentiometric titration.

49. PROCEDURE Using 100 cm3 volumetric flasks prepare of 0.02 M potassium dichromate solution and 0.10 M ammonium iron (II) sulphate solution. to add sufficient amount of dilute acid to prepare ammonium iron (II) sulphate solution. 2. Take 25 cm3 of given Fe2+ solution and add 25 cm3 dilute H2SO4 acid and 50 cm3 of distilled water in a 250 cm3 beaker. 3. SCE is used as the Reference electrode. Platinum metal foil, dipped in Fe2+ solution is used as the indicator electrode. 4. Standardise the potentiometer using a standard cell before replacing it with the working cell. 6. Add 2 cm3 of 0.02 M K2Cr2O7 solution from burette, operate the magnetic stirrer for 2 minutes, stop it, wait it for 1 minute and measure the E.M.F. 7. Repeat the above step, each time adding two more cm3 of K2Cr2O7 at a time and go on noting the E.M.F. after each addition. 8. When the volume reached near about 1 cm3 of the expected equivalence point (approximate), add the solution from burette in 0.5 cm3 instalments and note the potential each time.

50. Colorimetric Analysis of Fe 1.Thiocyanate method 2. 1 10-phenanthroline 3.Sulhosylicylic Acid 1,10-phenanthroline (C12H8N2, ortho-phenanthroline or o- Phen ) is a tricyclic nitrogen heterocyclic compound that reacts with metals such as iron, nickel, ruthenium, and silver to form strongly colored complexes. This property provides an excellent and sensitive method for determining these metal ions in aqueous solution. For example, o- Phen reacts with ferrous ion to produce a deeply colored red complex: at 508nm

51. Methods for Copper (Cu) 1. Redox Titration : Reactions : 1) 2 CuSO 4 + 4 KI Cu 2 I 2 + I 2 + 2 K 2 SO 4 2) I 2 + 2 Na 2 S 2 O 3 2 Nal + Na 2 S 4 O 6 Given : Na 2 S 2 O 3 Solution To find : Amount of copper Burette1 : Na 2 S 2 O 3 solution Burette2 : Diluted ore solution Indicator : Starch solution End point : Blue to white Calculations 1ml 0.025 N Na 2 S 2 O 3 = 0.001589 g Cu Procedure Neutralise the solution by adding dilute ammonia , add acetic acid 10% KI and two to three mal of Starch solution thenTitrate the liberated 12 with Na 2 S 2 O 3 solution till a pale yellow colour appears to the solution. Then add 1 to 2 ml. starch solution. The solution becomes blue. Continue the titration

52. Colorimetric method Ammonia at 620nm Complexometric Titration

53. Methods for Lead 1.Gravimetric estimation Chromate method

54. 2.Colorimetric methods Procedure : aliquot 10 mLsolution of lead in a 250 ml separating funnel ,add ammona – sulphide –cyanide solution then addition of dilute hydrogen chloride solution to adjust the pH 9.5 and add Dithiozone reagent in chloroform in to separating funnel shake well few minutes and allow to separating organic layer in to separate beaker .measure the absorbance against the blank solution at 510nm.

55. Calibration graph Graph absorbance Concentration of Lead

56. Determination of sodium by Flame photometry Procedure 1. Operate Flame Photometer according to the instructions provided for the equipment. 2. Run a series of suitable Na standards, and draw a calibration curve. 3. Measure Na in the samples (soil extracts) by taking the emission readings on the Flame Photometer at 589-nm wavelength. 4. Calculate Na concentrations by inferring to the calibration curve. Calculation

57. DETERMINATION OF POTASSIUM PRINCIPLE OF THE METHOD The sample is vaporised in an air-propane flame and the potassium compounds are atomised . The potassium atoms thus formed emit radiation of which the intensity is measured at a wavelength of 766.5 nm . RANGE AND DETECTION LIMIT This procedure yields a standard curve that is linear up to approximately 50 mg/L K. INTERFERENCES To prevent ionisation interferences, cesium is added to act as an ionisation buffer.

58. PRECISION AND ACCURACY The reproducibility of determinations by this procedure should give, at reasonable control and thorough sample preparation, a coefficient of variation within 5 % + 5 mmol /kg. APPARATUS Flame atomic emission spectrometer. REAGENTS A Stock Solution, K concentration 1000 mg/L Stock Solution, K concentration 1000 mg/L - Dissolve 1.9068 g potassium chloride, KCl in some water in a 1000-mL volumetric flask and make up to the mark with water.

59. The potassium chloride has to be dried at 200 C for at least 24 hours just before weighing. Just before drying, any lumps should be cut down so that only fine crystals remain. Standard Series - Pipette 0 – 1.00 – 2.00 mL of the stock solution into 100-mL volumetric flasks which already contain 40 mL water. Add either 4.5 mL concentrated sulphuric acid (96 %) 10 mL concentrated nitric acid (65 %) (digestion 2.3), 3.0 mL concentrated nitric acid (65 %) 1.0 mL concentrated hydrochloric acid (36 %) Let cool down and make up to the mark with water. This standard series has K concentrations of 0 – 10 – 20 mg/L. Calibration Curve - The emission counts are plot versus mg/L potassium in the standard series.

60. Thank You