Analysis Of Cations And Anions Group IV Experiment Title : Analysis of Cations and Anions

Analysis Of Cations And Anions Group IVI. Experiment Title : Analysis of Cations and AnionsII. Experiment Date : October 18th, 2014 at 07.00 amIII. End of The Experiment : October 18th, 2014 at 10.40 amIV.Experiment Purpose : 1. To determine the cation which can be found in the analite2. To determine the anion which can be found in the analiteV. Basic Theory

A. Qualitative AnalysisChemical analysis can be divided into two categories; qualitative analysis – what is present and quantitative analysis – how much is present. Qualitative ana-lysis involves the detection of elements that are found in an organic compound. Qualitative analysis can only detect the presence of elements in the compound but cannot determine the percentage or amount of them in the compound. For example; carbon and hydrogen are detected with the help of Liebig’s method. Some other common elements which can be determined are oxygen, halogen, sulphur, nitrogen, halogens, sulphur and phosphorus.Qualitative analysis is a type of chemical analysis which is used to separate

and detect cation and anions in a sample substance. The chemical properties of an

unknown substance are determined in the qualitative analysis procedure by the

reaction between the unknown substance and suitable reagents. The qualitative

analysis is used for the identification of a simple salt or the identification of various

cations present in a solution.

B. CationsCations are divided into five groups. A specific reagent for each group is used for their separation from the solution. This separation is

Experiment Report: Analysis of Anions and Cations 1

done in a particular se-quence because some ions of prior groups can also react with the reagent of later groups. This can be cause of difficulty in their separation. The qualitative analysis of cations depends on the solubility products of the ions. The cations get precipitated on the optimum needed concentration and easily detected.

1. Group I Cations

Cations: Ag+, Hg22+, and Pb2+Group I cations can be separated from the other groups since they form slightly soluble chlorides with the addition of hydrochloric acid (generally 1-2 M concentration). The other groups will remain in solution thus allowing the Group I chloride precipitates to be removed and further tested.Colour detection test is not suitable for their chlorides because all are white solid compounds. The analysing of group is done by adding the respective salt into water and follow it with dilute HCl. This results in a white precipitate in which NH4OH is added. The insoluble precipitate shows the presence of Plumbous (Pb2+) and if precipitate is soluble, and then it shows the presence of Argentous (Ag+). If the white precipitate turns black, it shows the presence of Hg22+. The reaction is:Ag+ + Cl- → AgCl↓ (white)

Hg22+ + 2Cl- →Hg2Cl2↓ (white)Pb2+ + 2Cl- → PbCl2↓ (white)

The obtained filtrate after first group analysis is used for the test of se-cond group. Usually Pb2+ is also included in the 2nd analytical group because the solubility of PbCl2 is more than the chlorides of other two ions. Confirmation Test


Lead (Pb2+) Silver (Ag+) Mercury (Hg2+)Pb2+ + 2KI → PbI2 + 2 K+ Pb2+ + K2CrO4 → PbCrO4 + 2K+

Ag+ + KI → AgI + K+ 2Ag+ + K2CrO4 → Ag2CrO4 + 2K+

Hg22++ 2KI → Hg2I2 + 2K+ 2Hg22+ + 2NaOH → 2Hg2O + 2Na+ + H2O2. Group II Cations

Cations: Cd2+, Bi3+, Cu2+, As3+, As5+, Sb3+, Sb5+, Sn2+, Sn4+ and Hg2+

The group reagent is H2S (at 0.2 - 0.3 M) which gives S2− ions in solutions. The tests are conducted in presence of dilute HCl to keep the S2- ion concen-tration at a minimum level. This round of tests helps only in second 2nd gro-up cations precipitation. The cations precipitation of the 4th group if present in the solution might occur in the absence of dilute HCl which can give wrong results. The use of sulphuric acid and nitric acid can cause to the precipitation of the 4th group cations and formation of colloidal sulphur respectively. This group is determined by the addition of the respective salt in water and then adding dilute HCl and then follow it by adding H2S. The reaction is: 3Hg2++2Cl-

+2H2S⟶Hg3S2Cl2↓+4H+Hg3S2Cl2↓+4H+⟶3HgS↓+2H++2Cl-

2As3++3 H2S⟶As2S3↓+6H+ 2AsO43-

+5H2S+6H+⟶As2S5↓+8H2O+ 2Sb3++3 H2S⟶Sb2S3↓+6H+ 2Sb5++5 H2S⟶Sb2S5↓+10H+

Cu2++H2S⟶CuS↓+2H+ Cd2++H2S⟶CdS↓+2H+ Sn2++H2S⟶SnS↓+2H+ Sn4++H2S⟶SnS2↓+4H+ 2Bi3++3 H2S⟶Bi2S3↓+6H+

The precipitate colour and the presence of the respective ions are shown in the table below. Experiment Report: Analysis of Anions and Cations 3

Precipitate Colour Presence of Cation

Reddish brown or black precipitate Bi3+, Cu2+, Hg2+ or Pb2+

Yellow precipitate Cd2+ or Sn4

Brown precipitate Sn2+

Red orange Sb3+

If the black or reddish brown precipitate comes, then it is boiled in dilu-ted HNO3. If the precipitate is insoluble in diluted HNO3 then Hg2+ is pre-sent. If it is soluble, then Cu2+, Bi3+ or Pb2+ can be present- I this solution sul-phuric acid is then added. A white precipitate shows that Pb2+ may be present; If no any precipitate forms, then an excess of ammonium hydroxide in the original salt solution is added. A blue colour indicates the presence of Cu2+ while a white precipitate indicates bismuth. For the yellow precipitate, an excess of NaOH is added to form a white precipitate. If the white precipitate dissolves, then Sn4+ is present; if it’s not then Cd2+ is present.Some of confirmation test for group II cationsLead (Pb2+) Copper (Cu2+)Pb2+ + 2KI → PbI2 + 2 K+ Pb2+ + K2CrO4 → PbCrO4 + 2K+

2Cu2+ + K4[Fe(CN)6] + CH3COOH → Cu2[Fe(CN)6] + 4K+

Cu2+ + 2NaOH → Cu(OH)2 + 2Na+ Cu(OH)2 → CuO + H2O (endothermic)Bismuth (Bi3+) Mercury (Hg2+)Bi3+ + 3KI (in excess) → BiI3 + 3K+BiI3 + KI → K[BiI4] Bi3+ + H2O (in excess) → BiO++

Hg2+ + 2KI (excess) → HgI2 + 2K+ HgI2 + 2KI → K2[HgI4] (red precipitate)2Hg2+ + SnCl2 → 2Hg + SnCl4 Experiment Report: Analysis of Anions and Cations 4

2H+ (gray white precipitate)3. Group III Cations

Cations: Fe2+, Fe 3+, Al3+, Cr3+, Cr4+, Co2+, Mn2+, Mn4+, Zn2+

Cations of this group do not react either with dilute hydrochloric acid or with hydrogen sulphide in dilute mineral acid medium. However they form precipitates with ammonium sulphides (NH4)2S in neutral or ammonical medium. The reaction is:

Co2++S2-⟶CoS↓ Ni2++S2-⟶NiS↓ Mn2++S2-⟶MnS↓ Zn2++S2-⟶ZnS↓

Fe3++3NH3+3H2O⟶Fe(OH)3↓+3NH4+

Al3++3NH3+3H2O⟶Al(OH)3↓+3NH4+

Cr3++3NH3+3H2O⟶Cr(OH)3↓+3NH4+

The group detection is carried out by preparing a respective salt solution in water and then adding NH4Cl and NH4OH. If a reddish brown precipitate form then Fe3+ is present, a gelatinous white precipitate shows Al3+, and a green precipitate is for Cr3+ or Fe2+. The Cr3+ or Fe2+ is identified by adding excess of sodium hydroxide to the green precipitate. The soluble precipitate indicates Fe2+, otherwise Cr3+ is present.

4. Group IV Cations


Cations: Ba2+, Sr2+, Ca2+Cation of this group do not react with the reagents the reagents of groups I, II, III. They precipitate with ammonium carbonate (NH4)CO3 in the pre-sence of ammonium chloride in neutral medium. The result of experiment and the presence of the respective ions are shown in the table below. Result of Experiment Presence of Cation

Yellow precipitate Ba2+

Red flame Sr2+

Red-brick flame Ca2+

White crystal Ag+

Reaction which occur in analysing group IV cations:Ba2++CO32-⟶BaCO3↓Sr2++CO32-⟶SrCO3↓Ca2++CO32-⟶CaCO3↓5. Group V Cations

Cations: Mg2+, Na+, K+, NH4+ Common cations, which do not react with reagents of the previous groups, form the last group of cations. It can be identified by special reaction or by flame test. Magnesium cation showing similar reaction with group IV cations. Sodium and potassium ion are from group IA (Alkaline), and they have similarity. Both of them are big enough, colourless, can not reduced in solution state, so it can not react with water. The reaction is: Magnesium:MgCl5.6H2O + Magnusson 1 → Blue precipitate


MgCl5.6H2O + oxine → Mg(C9H6NO)2+ 4H2O (yellow) Amonium: NH4+ + OH- → NH3(g) + 6H2O(g) Natrium:Na+ + Mg2+ + 3UO22+ + 9CH3COO- + 6H2O → NaMg(UO2)3(CH3COO)9 (yellow crystalline precipitate)


Na+ + Zn2+ + 3UO22+ + 9CH3COO- + 6H2O → NaZn(UO2)3(CH3COO)9 (yellow crystalline precipitate) Reaksi Kalium:K++Na[Co(NO2)6] → K3[Co(NO2)6]↓(yellow preciptate)C. Anions

The methods available for the detection of anions are not as systematic as those which have been described above for cations. No really satisfactory scheme has yet been proposed which permits the separation of the common anions into major groups, and the subsequent unequivocal separation of each group into its independent constituents; however, it is possible to detect anions individually in most cases, after perhaps a 1-2 stage separation. It is advantageous to remove all heavy metals from the sample by extracting the anions through boiling with sodium carbonate solution; heavy metal ions are precipitated out in the form of carbonates, while the anions remain in solution accompanied by sodium ions.The following scheme of classification of anions has been found to work well in practice; anions are divided into four groups on the basis of their reactions with di-lute hydrochloric acid and of the differences of solubilities of their barium and sil-ver salts.

1. Group 1 Anions

Anions: CO32-, SiO32-, S2-, SO32-, S2O32-The anions in this group are visible change, gas evolution and or for-mation of a precipitate, with dilute hydrochloric acid. The reaction is:

CO32-+Ca2+⟶CaCO3↓ SO32-+Ag+⟶ [AgSO3]-

[AgSO3]-+Ag+⟶Ag2SO3↓Experiment Report: Analysis of Anions and Cations 8

S2-+Pb2+⟶PbS↓2. Group II Anions

Anions: SO42-, PO43-, F-, or BO33-The anions of this group do not react with hydrochloric acid, but form preci-pitates with barium ions in neutral medium. The reaction is:

SO42-+Ba2-⟶BaSO4↓ HPO42-+Mg2++NH3⟶MgNH4PO4↓

3. Group III Anions

Anions: Cl-, Br-, I-, SCN-Anions of this group do not react either with dilute hydrochloric acid, or with barium ions in neutral medium. However, they form precipitates with silver ions in dilute nitric acid medium.

Cl-+Ag+⟶AgCl↓ Br-+Ag+⟶AgBr↓ 4I-+2Cu2+⟶2CuI↓+I2Brown precipitate

4. Group VI Anions

Anions: NO3-, NO2-, ClO3-Common anions, which do not react with reagents of the previous groups, form the last group of anions. To identify nitrate ion can be done by brown ring test which can be done by adding concentrate H2S04 and then adding saturated FeSO4 little by little through the tube wall. The reaction is:2NO3-+4H2SO4+6Fe2+⟶6Fe3++2NO↑+4SO42-+4H2OFe2++NO↑⟶Fe(NO)]2+

Brown ringVI. Tools and MaterialA. Tools B. Materials


1.2.3.4.5.6.7.8.9.

Test tubePipettesLitmus paperTest tube rackFilter paperTripodFunnelBeaker glassBunsen burner

1.2.3.4.5.

Sample (NH4NO3)NaOH solutionSaturated Na2CO3Concentrated H2SO4Saturated FeSO4

VII. Flow ChartA. NH4

+ Cation Test

B. Authentication of NO3- ion


Original Substances

3 Drops of solution A bit of Crystal

Turn Litmus to blue Smell of -Enter to test tube

-Heat it

-Added 6drops of NaOH

-Test with litmus (red) by enter half of litmus to the test tube

Original SubstancesResidue Filtrate

Brown Ring

-Added concentrated H2SO4-added saturated FeSO4 little by little through the tube wall

Heated with Na2CO3


VIII. Result Of The Experiment

Experiment ProcedureResult of The Experiment

Assumption/Reaction ConclusionBefore After

A. NH4+ Cation Test Sample: color-

less crystals

NaOH: colorless

solution

Litmus paper:

red

Sample+NaO

H→Colorless

solution

Litmus paper:

blue

NH4+ + OH- → NH3(g) + 6H2O(g) Cation which contain

in the sample no 2 is

NH4+, it can be pro-

ven by turning red lit-

mus paper to blue

A. NH4+ Cation Test Sample: color-

less crystals

Na2CO3: color-

less solution

Sample+ Na2CO3 → Colorless solu-tionAfter heated: white precipitate

2NO3-+4H2SO4+6Fe2+ ⟶ 6Fe3++2NO↑+ 4SO42-

Anion which contain

in the sample no 2 is

NO3-, it can be pro-

ven by forming brown

Experiment Report: Analysis of Anions and Cations

Original Substances

3 Drops of solution A bit of Crystal

Turn Litmus to blue Smell of

-Enter to test tube

-Heat it

-Added 6drops of NaOH

-Test with litmus (red) by enter half of litmus to the test tube

Original SubstancesHeated with Na2CO3

12

H2SO4: color-

less solution

FeSO4: yellow

solution

formedFiltrate+ H2SO4→ colorless solutionFiltrate + H2SO4 + FeSO4→ brown ring formed

+4H2OFe2++NO↑⟶ Fe(NO)]2+Brown ring

ring


Residue Filtrate-Added concentrated H2SO4-added saturated FeSO4 little by little

13

IX.AnalysisIn this experiment we got sample number two which has form colourless crystal through random selection. First of all we are dividing the sample into three with ratio 2:2:1. The first two is for cations test, another two is for anion test and the last is for testing NH4+ cations, here is the experiments

A. NH4+ Cation Test

In this experiment is analysing NH4+ cation. First, we are entering some of the sample into reaction tube. Then, we adding 6 drops of NaOH to the tube, the sample turn its form from colourless crystals to colourless solution. After that, we are put the red litmus paper above the tube and enter the half part of the litmus into the tube. After a while the red lit-mus paper changes its colour from red to blue. The reaction is:NH4+(s) + OH-(aq) → NH3(g) + 6H2O(aq)

The changing colour of the litmus indicates that in the sample number two contain NH4+ cation.B. Preparation of Anion Test

In this experiment we analysing the contents of anion in the sample number two. First we adding saturated Na2CO3 into the sample, the sample turn its form from colourless crystal to colour solution. Then, we heating the solution with steam bath water for about 10 minutes until white sediment formed. Next, the heating result is filtered. We obtain colour-less solution as the filtrate which will be used for anion test. Then, we are dividing the filt-rate into 3 for testing anion contents. C. Authentication of NO3

- ion

In this experiment we authenticate anion NO3- in the sample number two. First, we adding 2 drops of concentrate H2SO4 into the test tube which contains filtrate from prepa-ration solution. Then, we are adding saturated FeSO4 little by little through the tube wall until the brown ring is formed. The reaction is:Experiment Report: Analysis of Anions and Cations 14

2NO3-+4H2SO4+6Fe2+⟶6Fe3++2NO↑+4SO42-+4H2OFe2++NO↑⟶Fe(NO)]2+Brown ring

X. ExplanationA. NH4

+ Cation Test

This experiment has purpose to determine the cation which contain in the sample, in this case NH4+ cation. Here we using original sample because during the course of analysis most of the group reagents are added in the form of ammonium compound, thus by the time group V is reached, a considerable amount of ammonium ions will be built up in the test solution. The first thing that we have do is entering some of the sample into reaction tube. Then, we adding 6 drops of NaOH to the tube, the sample turn its form from colourless crystals to colourless solution. After that, we are put the red litmus paper above the tube and enter the half part of the litmus into the tube. After a while the red litmus paper changes its colour from red to blue because the reaction produce ammonia (NH3) gases which is base that can be identified from its smells and changing of litmus paper from re to blue. The reaction is:

NH4+(s) + OH-(aq) → NH3(g) + 6H2O(aq)The changing colour of the litmus indicates that in the sample number two contain NH4+ cation.

B. Preparation of Anion Test

In this experiment we analysing the contents of anion in the sample number two. First we adding saturated Na2CO3 into the sample, the sample turn its form from colourless crystal to colour solution. Then, we heating the solution with steam bath water for Experiment Report: Analysis of Anions and Cations 15

about 10 minutes until white sediment formed. Extracting anions through boiling with sodium carbonate solution has purpose to remove all heavy metals from the sample, because the heavy metal ions are precipitated out in the form of carbonates, while the anions remain in solution accompanied by sodium ions. Next, the heating result is filtered. We obtain colour-less solution as the filtrate which will be used for anion test. Then, we are dividing the filt-rate into 3 for testing anion contents.

C. Authentication of NO3- ion

In this experiment we authenticate anion NO3- in the sample number two. First, we adding 2 drops of concentrate H2SO4 into the test tube which contains filtrate from prepa-ration solution. Then, we are adding saturated FeSO4 little by little through the tube wall until the brown ring is formed. The reaction is:2NO3-(aq)+4H2SO4(aq)+6Fe2+(aq)⟶6Fe3+(s)+2NO↑(g)+4SO42-(aq)+4H2O(l)Fe2++NO↑⟶Fe(NO)]2+

Brown ringThis brown ring are caused by formation of [Fe(NO)]2+. The overall reaction is the reduction of the nitrate ion by iron(II) which is reduced to iron(I) and formation of a nitrosonium complex where nitric oxide is oxidized to NO1+. In this experiment exothermic reaction are occur because existence of H2SO4 and it makes the tube feels hot because the heat moves from system to surrounding. From this experi-ment, we know that in the sample number two contain of NO3- anion.XI. ConclusionQualitative analysis deals with the anions and cations which contain in a sample. To analyse cations and anions have different way for each ion. To identify group I-IV cation can be done by precipitation. For group I, HCl is used as precipitator. Then, for group Experiment Report: Analysis of Anions and Cations 16

II, the precipitator is H2S. For group III, (NH4)2S is used as the precipitator and (NH4)2CO3 is used as precipitator for Group IV. Meanwhile, for Group V is different for each ions, it also can be done by flame test for group V. To identify anions are different for each ion, but before done further test, the sample should be heated with sodium carbonate to remove all heavy metals. In this experiment we know that in the sample number two is NH4NO3 after doing some test toward the sample. NH4+ cation can be identified by it smells and changing colour of litmus paper from red to blue. Then, the existence of NO3- anion can be identified by brown ring test.XII. Answer of the Question1. Write down the common reaction for each group!Answer:

Group I A++Cl-⟶ACl(s)A+ is Ag+ A2++Cl-⟶ACl2(s)A2+ is Pb2+, Hg2+ White precipitate

Group II A2++S2-⟶AS(s)A2+ is Hg2+, Pb2+, Cu2+, Cd2+ 2A3+ + S2- ⟶ A2S3 (s)A3+ is Bi3+, As3+, Sb3+ A4+ + S2- ⟶ AS2 (s)A4+ adalah Sn4+

HgS. PbS, CuS precipitate is black. CdS, As2S3, SnS2 precipitate is yellow. Bi2S3, SnS precipitate is brown. Sb2S3,Sb2S5 precipitate brown. Group III


A2+ + 2OH- ⟶ A(OH)2 (s)A2+ is Mn2+, MO.XH2O A3+ + 2OH- ⟶ A(OH)3 (s)A3+ is Fe3+, Al3+, Cr3+, M2O3.XH2O A2+ + S2- ⟶AS(s)A2+ is Zn2+, Co2+, Ni2+

FeS, NiS, CoS is black precipitate. Al(OH)3, ZnS is white precipitate. Cr(OH)3 is green precipitate. Mangan(II) Sulphide is red guava sul-phide. Group IV

A2+ + CO32- ⟶ ACO3 (s)A2+ is Ba2+, Sr2+, Ca2+White precipitate

Group VIn this group special reaction are used such as flame test which used to identify group V ions. Besides that, for testing Mg can be done by Na2HPO4 testing, and for testing NH4+ can be done by direct test toward the original sample2. Why oxidizer which used in cation analysis in H2S system is H2O2 or brome water,

and not HNO3?Answer:The using of H2O2 or brome water as an oxidizer in H2S system because it’s easily to evaporate so we can get sulphide salt precipitate from H2S, furthermore H2O2 or brome water is an oxidizer which can react in both acid and base ambience. It’s different to HNO3 which also an oxidizer, but its ability is depending on acid concentration and solution temperature. Meanwhile, when a substance reacts with HNO3, it will form S element, so it’s not appropriate if it used as an oxidizer because H2S is used as precipitator in inorganic qualitative analysis.3. How could we know that H2S, H2O2, or Br is no more exist in the solution?Experiment Report: Analysis of Anions and Cations 18

Answer: To know that H2S is no more exist is by using Pb-acetate paper. If there are no spotted in Pb-acetate paper it means the absence of H2S To know that H2O2 is no more exist in the solution by using filter paper which immersed on HCl, put the paper on the hose’s hole, if there is no black stain. It means the absence of H2O2 To know that Br2 is no more exist in the solution is by evaporate the solution. Put the wet kanji paper on the smoke. If the paper turn to orange it means the absence of Br24. Why to determine the existence of NH4+ cation, we have to use the original sample?Answer:We using original sample because during the course of analysis most of the group reagents are added in the form of ammonium compound, thus by the time group V is reached, a considerable amount of ammonium ions will be built up in the test solution. It has purpose to make the analysis more accurate.5. What is the common reaction in making preparation solution to analyse anion in the sample?Answer:If the sample is M bivalent metal in an HA acid, the reaction which occurs is:

MA2 + Na2CO3 ⟶2NaA + MCO3

6. Precipitation of sulphide salt on group II and IIIB cation analysis done in differ-rent solution ambience. Explain!Answer:On group II, H2S flowed in acid solution, so the H2S gases just a little bit dissolved and so much gas which is not absorbed in sulphide salt precipitation. It can be done in acid ambience, Experiment Report: Analysis of Anions and Cations 19

because if the acidity which got from dilute HCl is too low, so the sulphides from group IIIB will precipitate (NiS, CoS, and ZnS)It’s different to group IIIB, H2S gas is distribute to basic solution which contain many ammonium salt. H2S will much absorbed, it make group IIIB precipitate. Furthermore, basic ambience also decreases the oxidation of sulphides to sul-phate which is easy to dissolve.7. Why the precipitations in group IV have to be done in basic ambience?Answer:Because in basic ambience (existence of ammonia), can prevent the precipitation of magnesium and also to make carbonate (Ca, Sr, Ba) salts precipitate by ammo-nium carbonate solution. It also because the difference among Mg, Ca, Sr and Ba.

XIII. Referencess


Day, R.A, jr & Underwood, A.L. 2002. Analisis Kimia Kuantitatif: Edisi keenam. Jakarta: PT. Gelora Aksara Pratama. (Tranlated from Day, R.A, jr & Underwood, A.L. 1998. Quantitative Analysis: Sixth Edition. New York: Prentice-HallHelmenstine ,Anne Marie, Ph.D. 2010. Qualitative Analysis: Introduction to Qualitative Analysis-Identifying Anions and Cations.(online). ( http://chemistry.about.com/od/lectureclassnotes/a/Qualitative-Analysis.htm ), (accessed on October, 13th 2014, 17.00) Noname.2013.Classification of the cations and anions .(online). (www.inc.bme.hu/en/subjects/inchem/sillabus/129-145.pdf ), (accessed on October, 13th 2014, 19.30) Setiono, L and Handayana, P.A.(1985). Vogel: Buku Teks Analisis Oraganik Kualitatif Makro dan Semimikro.(first edition). Jakarta: Kaliman Media Pusaka.(Translated from Svehla, G. 1979. Vogel’s: Text Book of Macro and Semimicro Qualitative Inorganic Analysis. (fifth edition). London: Limited Group Ltd.Tim Kimia Dasar. 2014. Panduan Praktikum Kimia Analitik I Dasar-Dasar Kimia Analitik. Surabaya: Jurusan Kimia FMIPA Unesa


http://www.inc.bme.hu/en/subjects/inchem/sillabus/129-145.pdf

http://chemistry.about.com/od/lectureclassnotes/a/Qualitative-Analysis.htm

http://chemistry.about.com/od/lectureclassnotes/a/Qualitative-Analysis.htm

ATTACHMENTNH4

+ Cation Test


Original Sample no 2Colourless crystalDivide the sample into 3 with ratio 2:2:1

NaOHColourless solution

Sample+6 drops of NaOHColourless solutionPut red litmus paper above the tube

Red litmus paper turns to blue it indicate the

Red litmus paper

22

Making preparation solution


Divide the sample into 3 with ratio 2:2:1Saturated FeSO4Yellow solutionSaturated Na2CO3Colourless solution

Concentrated H2SO4Colourless solution Sample+Saturated Na2CO3Colourless solutionAfter heating processWhite precipitate

Residue from filtrationWhite precipitateFiltrate from filtrationColourless solution

23

Authentication of NO3- ion


Divide the filtrate from preparation solution into 3 for further anion test

Filtrate of prepa-ration solution+ concentrate HSO4Colourless solutionFiltrate of prepa-ration solution+ saturated FeSO4 Brown ring begin to formed

Filtrate of prepa-ration solution+ saturated FeSO4 Brown ring formed

24

Documents

Analysis Of Cations And Anions Group IV Experiment Title : Analysis of Cations and Anions