contents qualitative analysis syllabus ... in our scheme fe2+ is not there even if it is present,...

Topic Page No.

Theory 01 - 05

Exercise - 1 06 - 11




Answer Key 31 - 35

Contents

QUALITATIVE ANALYSIS

SyllabusQUALITATIVE ANALYSIS

Principles of qualitative analysis :Groups I to V (only Ag+, Hg2+, Cu2+, Pb2+, Bi3+, Fe3+, Cr3+, Al3+, Ca2+, Ba2+,Zn2+, Mn2+ and Mg2+); Nitrate, halides (excluding fluoride), sulphate andsulphide.

Name : ____________________________ Contact No. __________________

QUALITATIVE ANALYSIS_ADVANCED # 1A-479 Indra vihar, kota

Ph. - 9982433693 (NV Sir) 9462729791(VKP Sir)Physical & Inorganic By

NV SirB.Tech. IIT Delhi

Organic Chemistry By

VKP SirM.Sc. IT-BHU

QUALITATIVE ANALYSIS

Some important points which should be kept in mind while doing the analysis of cations.

1. Group 1st radicals (Ag+, Pb2+

, Hg2

2+) are precipitated as chloride because the solubility product of thesechlorides (AgCl, PbCl2 , HgCl2) is less than the solubility products of chlorides of all other metal ions, whichremain in solution. Lead chloride is slightly soluble in water and therefore, lead is never completely precipitatedby adding dilute hydrochloric acid to a sample ; the rest of the lead ions are precipitated with H2S in acidicmedium together with the cations of the second group.

2. Group 2nd radicals are precipitated as sulphides because of their low solubility products whereas sulphidesof other metals remain in solution because of their high solubility products. HCl acts as a source of H+ whichdecreases the concentration of S2– due to common ion effect. Hence, the concentration of S2– ion is too lowthat it exceeds only the solubility products of the metal sulphides of IInd group.We can not use H2SO4 inplace of HCl because some cations of higher groups i.e. vth group will also precipitateas their sulphates like BaSO4, SrSO4, CaSO4 etc.HNO3 can't be used in place of HCl. HNO3 is a powerful oxidising agent. HNO3 will oxidize H2S formingsulphur (yellow precipitate) or colloidal solution causing confusion with CdS, As2S3 even though Cd2+ , As3+

will be absent. The colloidal solution is white-yellow and that cannot be filtered causing unnecessary trouble.

3. Group 3rd radicals are precipitated as hydroxides and the addition of NH4Cl suppresses the ionisation ofNH4OH so that only the group 3 cations are precipitated as hydroxides because of their low solubilityproducts.(i) Excess of NH4Cl should not be added, as manganese will precipitate as MnO2.H2O(ii) (NH4)2SO4 cannot be used in place of NH4Cl because the SO4

2– will also give the precipitate of BaSO4,SrSO4 etc.(iii) While proceeding for 3rd group from 2nd group, the filtrate of 2nd group is boiled off to remove the dissolvedH2S and then one drop of concentrated HNO3 is added and again boil so that if Fe2+ is present is oxidised toFe3+. The Ksp of Fe2+ is higher than Fe3+, therefore, it is partially precipitated and will thus interfere in theanalysis of 4th group radicals. In our scheme Fe2+ is not there even if it is present, we shall report only Fe3+

(Fe2+ needs other special tests).(iv) If the medium remains acidic the hydroxides do not precipitate and we would think that Fe3+, Al3+, Cr3+ areabsent even though they may be present.(v) In place of NH4OH, NaOH solution can't be used for the precipitation as their hydroxides because inexcess of it we get soluble complexes of Al3+ and Cr3+.

4. In 4th group, ammonium hydroxide increases the ionisation of H2S by removing H+ from H2S as unionisedwater.

H2S 2H+ + S2– ; H+ + OH– H2ONow the excess of S2– ions is available and hence the ionic products of group 4th group cations exceeds theirsolubility products and will be precipitated. In case H2S is passed through a neutral solution, incompleteprecipitation will take place due to the formation of HCl, which decreases the ionisation of H2S. For example

MnCl2 + H2S MnS + 2HCl

5. In 5th group the reagent ammonium carbonate should be added in alkaline or neutral medium. In theabsence of ammonia or ammonium ions, magnesium will also be precipitated.





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Physical Examination Of the Mixture :

The physical examination of the unknown mixture involves the study of colour, smell and density.

Table : 1

Physical Examination

Experiment Observations Inference

(a) Colour Blue or Bluish green Cu2+ or Ni2+

Greenish Ni2+

Light green Fe2+

Dark brown Fe3+

Pink, violet Co2+

Light pink, flesh colour or dullearthy colour Mn2+

WhiteShows the absence of

Cu2+,Ni2+,Fe2+,Fe3+

Mn2+, Co2+

(b) SmellAmmonical smell NH4

+

Vinegar like smell CH3COO–

Smell like that of rotten eggs S2–

(i) Heavy Salt of Pb2+ or Ba2+–

(ii) Light fluffy powder Carbonate salts

(d) DeliquescenceSalt absorbs moisture and

becomespaste like

(i) If coloured, may be Cu(NO3)2,

FeCl3(ii) If colourless, may be

Zn(NO3)2, chlorides of Zn2+, Mg2+ etc.

Take a pinch of the salt between your fingers and rub with a drop of

water

(.C) Density

Dry Heating Test :

This test is performed by heating a small amount of mixture in a dry test tube. Quite valuable information can

be generated by carefully performing and noting the observations here. On heating some salts undergo

decomposition thus evolving the gases or may undergo characteristic changes in the colour of residue.

These observations are tabulated below along with the inferences that you can draw.





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Table : 2

OBSERVATION INFERENCE1. Gas evolved

(a) Colourless and odourless gasCO2 gas – turns lime water milky CO3

2–

(b) Colourless gas with odour(i) H2S gas–Smells like rotten eggs, turns Hydrated S2–

lead acetate paper black.(ii) SO2 gas–Characteristic suffocating SO3

2–

smell, turns acidified potassium dichromatesolution or paper green.

(iii) HCl gas – Pungent smell, white fumes with Cl–

ammonia, white precipitate with silver nitrate solution.(iv) Acetic acid vapours–Characteristic vinegar CH3COO–

like smell.(v) NH3 gas– Characteristic smell, turns NH4

+

Nessler's solution brown.

(c) Coloured gases – Pungent smell(i) NO2 gas – Reddish brown, turns ferrous NO2

– or NO3–

sulphate solution black.(ii) Cl2 gas – Greenish yellow, turns starch Cl–

iodide paper blue.(iii) Br2 vapours – Reddish brown, turns starch Br–

paper orange red.(iv) I2 vapours – Dark violet, turns starch paper blue. –

2. Sublimate formed(a) White sublimate NH4

+

(b) Black sublimate accompanied by violet vapours. –

3. FusionThe mixture fuses. Alkali metal salts or salt containing

water of crystallisation.4. Swelling

The mixture swells up into voluminous mass. PO43– , BO3

3– indicated

5. Residue(i) Yellow when hot, white when cold. Zn2+

(ii) Brown when hot and yellow when cold Pb2+

(iii) Original salt blue becomes white on heating Hydrated CuSO4 indicated(iv) Coloured salt becomes brown or black on Co2+ , Fe2+, Fe3+ , Cr3+ , Cu2+ , Ni2+ , Mn2+

heating. indicated.





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Note : Use a perfectly dry test–tube for performing this test. While drying a test–tube, keeps it in slanting

position with its mouth slightly downwards so that the drops of water which condense on the uppercooler parts, do not fall back on the hot bottom, as this may break the tube.

Charcoal Cavity Test :This test is based on the fact that metallic carbonates when heated in a charcoal cavity decompose to givecorresponding oxides. The oxides appear as coloured incrustation or residue in the cavity . In certain cases,the oxides formed partially undergo reduction to the metallic state producing metallic beads or scales.Example :

(a) ZnSO4 + Na2CO3 ZnCO3 + Na2SO4

ZnCO3 ZnO (Yellow when hot, white when cold) + CO2

(b) CuSO4 + Na2CO3 CuCO3 + Na2SO4

CuCO3 CuO + CO2CuO + C Cu (Reddish scales) + CO

Table : 3

InferenceIncrustation or Residue Metallic bead

Yellow when hot, white when cold None Zn2+

Brown when hot, yellow when cold Grey bead whichmarks the paper Pb2+

No characteristic residue Red beads or scales Cu2+

White residue which glows on heating None Ba2+,Ca2+, Mg2+

Black None Nothing definite–generally coloured salt

Observation

Cobalt Nitrate Test :In case the residue is white in colour after charcoal cavity test, add a drop of cobalt nitrate in the charcoalcavity. A drop of water is then added and the mass is heated in an oxidising flame using blow pipe. It is cooledand one or two drops of cobalt nitrate solution is added and then again heated in the oxidising flame. Differentmetal salts give different coloured mass as given in the table. To illustrate :

ZnSO4 + Na2 CO3 ZnCO3 + Na2 SO4 ; ZnCO3 ZnO + CO2

2Co (NO3)2 2CoO + 4 NO2 + O2 ; ZnO + CoO ZnO. CoO (or CoZnO2) (Rinmann's green)

Table : 4





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Flame test :The chlorides of the metals are more volatile as compared to other salts and these are prepared in situ bymixing the compounds with a little concentrated hydrochloric acid. On heating in a non-luminous Bunsenflame they are volatilized and impart a characteristic colour to the flame as these absorb energy from theflame and transmit the same as light as characteristic colour .

Table : 5

Colour of Flame Inference

Crimson Red / Carmine Red LithiumGolden yellow Sodium

Violet/Lilac PotassiumBrick red CalciumCrimson Strontium

Apple Green/Yellowish Green BariumGreen with a Blue centre/Greenish Blue Copper

Borax Bead test :

On Heating borax forms a colourless glassy bead of NaBO2 and B2O3 .Na2B4O7.10H2O Na2B4O7 2NaBO2 + B2O3On heating with a coloured salt , the glassy bead forms a coloured metaborate in oxidising flame.

For example, in oxidising flame copper salts give blue bead.CuSO4 CuO + SO3 ; CuO + B2O3 Cu(BO2)2 (blue bead)

However, in reducing flame the colours may be different due to different reactions.2Cu(BO2)2 + C 2CuBO2 + B2O3 + CO2Cu(BO2)2 + 2C 2Cu (brown red/red and opaque bead) + 2B2O3 + 2CO.

Table : 6

When Hot When Cold When Hot When Cold

Copper Green Blue Colourless Brown red

Iron Brown yellow Pale yellow/Yellow Bottle green Bottle green

Chromium Yellow Green Green Green

Cobalt Blue Blue Blue Blue

Manganese Violet/Amethyst Red/Amethyst Grey/Colourless Grey/Colourless

Nickel Violet Brown/Reddish brown Grey Grey

Colour in oxidising flame Colour in reducing flameMetal

Non luminous flame is called oxidising flame.

Luminous flame is called reducing flame.

All acid radicals which are in JEE syllabus are colourless and diamagnetic. Hence the colour of thesalts is only due to the basic radicals.





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OBJECTIVE QUESTIONS

* Marked Questions are having more than one correct option.

Acid radicals (Anions)1. Dilute H2SO4 group

1.1 Sodium carbonate extract is a mixture of :(A) [Salt + Na2CO3 + HCl] (B) [Salt + Na2CO3 + H2O](C) [Salt + CaCO3 + HCl] (D) [Salt + Na2CO3 + HNO3]

1.2 For the test of sulphite, the soda extract is acidified with :(A) dil HCl (B) dil HNO3 (C) CH3COOH (D) None of these

1.3 Which of the following gives a suffocating gas when treated with dilute HCl ?(A) Carbonate (B) Sulphite (C) Sulphate (D) Borate

1.4* The carbonate of which of the following cation is soluble in water ?(A) Na+ (B) K+ (C) NH4

+ (D) Ca2+

1.5 The mixture when rubbed with organic acid smells like vinegar obtain. It contains :(A) sulphur (B) nitrate (C) nitrite (D) acetate

1.6 Colourless salt (A) + dil. H2SO4 or CH3COOH + Kl blue colour with starch. (A) can be :(A) K2SO3 (B) Na2CO3 (C) NH4NO2 (D) NH4Cl

1.7* Zinc pieces are added to acidified solution of SO32 – . Gas liberated can :

(A) turn lead acetate paper black. (B) turn lime water milky.(C) give white precipitate with AgNO3 solution. (D) decolourize acidified KMnO4 solution.

1.8 A mixture when rubbed with dilute acid smells like vinegar. It contains :(A) sulphite (B) nitrate (C) nitrite (D) acetate

1.9 A substance on treatment with dilute H2SO4 liberates a colourless gas which produces (i) turbidity withbaryta water and (ii) turns acidified dichromate solution green. The reaction indicates the presence of :(A) CO3

2– (B) S2– (C) SO32– (D) NO2

–

1.10 An inorganic compound ‘A’ is dissolved in dilute hydrochloric acid and is then warmed. A colourless gas ‘B’is produced. When a filter paper moistened with potassium iodate and the starch solution is exposed to thegas it turns blue. The gas B and the compound A are :(A) SO2 and Na2SO3 (B) SO3 and Na2SO4 (C) H2S and Na2S (D) H2S and Na2SO3

1.11 Which of the following combines with Fe() ions to form a brown complex?(A) N2O (B) NO (C) N2 O3 (D) N2O4

1.12* Which of the following statements is/are incorrect ?(A) A filter paper moistened with cadmium acetate solution turns yellow, when brought in contact with H2Sgas.(B) Both carbonate ions as well as bicarbonate ions in the solutions, give reddish-brown precipitate withmercury(II) chloride.(C) Sulphites in presence of zinc, reacts with dilute H2SO4 to liberate SO3 gas.(D) A filter paper moistened with KIO3 and starch turns blue in contact with SO2 vapours.





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2. Concentrated H2SO4 group2.1 The chromyl chloride test is meant for which of the following ions ?

(A) Cl– ions (B) Both Cl– and Br– ions(C) I– ions (D) Cl– and CrO4

2– ions

2.2 Which of the following reagents turns white precipitate of AgCl yellow ?(A) NaI (B) Na3AsO3 (C) Na3AsO4 (D) NaCN

2.3 When a mixture of solid NaCl and solid K2Cr2O7 is heated with concentrated H2SO4, deep red vapours areobtained. This is due to the formation of :(A) chromous chloride (B) chromyl chloride (C) chromic chloride (D) chromic sulphate

2.4 AgCl dissolves in ammonia solution giving :(A) Ag+, NH4

+ and Cl– (B) Ag(NH3)+ and Cl– (C) Ag2(NH3)2+ and Cl– (D) Ag(NH3)2+ and Cl–

2.5 Violet vapours are given out when ........... is treated with conc. H2SO4 :(A) bromide (B) iodide (C) chloride (D) nitrate

2.6 A mixture upon adding conc. H2SO4 gives deep red fumes. It may contain the anions pair :(A) Cr2O7

2 – and Cl– (B) Br – and Cr2O72 – (C) NO3

– and Cl – (D) CrO42 – and NO3

2 –

2.7 A solution of a salt in concentrated sulphuric acid produced a deep blue colour with starch iodide solution.The salt may be :(A) chloride (B) carbonate (C) acetate (D) bromide

2.8 AgCl react with NH3 & forms a complex :(A) AgNO3 (B) Ag NH2Cl (C) Ag (NH3)2 Cl (D) Ag mirror

2.9 A colourless solution of a compound gives a precipitate with AgNO3 solution but no precipitate with a solutionof Na2CO3 . The action of concentrated H2SO4 on the compound liberates a suffocating reddish brown gas.The compound is :(A) Ba(CH3COO)2 (B) CaCl2 (C) NaI (D) NaBr

2.10 When chlorine (Cl2) water in excess is added to a salt solution containing chloroform, chloroform layer turnspale yellow/orange Salt contains :(A) Br– (B) – (C) NO3

– (D) S2–

2.11 An aqueous solution of salt containing an acidic radical X– reacts with sodium hypochlorite in neutral medium.The gas evolved produces blue black colour spot on the starch paper. The anion X– is :(A) CH3COO– (B) Br– (C) I– (D) NO2

–

2.12 When chlorine water is added to an aqueous solution of potassium halide in the presence of chloroform, acolour is developed but on adding more of chlorine water the colour disappears, and a colourless solution isobtained. This test confirms the presence of the following in aqueous solution.(A) Iodide (B) Bromide (C) Chloride (D) Iodide and bromide

2.13 Nitrate is confirmed by ring test. The brown colour of the ring is due to formation of :(A) ferrous nitrite (B) nitroso ferrous sulphate(C) ferrous nitrate (D) FeSO4 .NO2

2.14 Nitrates of all the metals except mercury and bismuth are :(A) coloured (B) unstable (C) soluble in water (D) insoluble in water

2.15* Which of the following reagents can be used for making the distinction between AgCl and AgI ?(A) Sodium arsenite solution. (B) Dilute ammonia solution.(C) Potassium cyanide solution. (D) Dilute HNO3.





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3. Precipitation Reactions3.1 Precipitate of PbSO4 is soluble in :

(A) ammonium acetate (6M) (B) dilute HCl(C) dilute H2SO4 (D) none

3.2 There are four test tubes containing dilute HCl, BaCl2, CdCl2 and KNO3 solutions. Which of the followingreagents will help in the identification of BaCl2 ?(A) NaOH (B) K2CrO4 (C) AgNO3 (D) both (B) and (C)

Basic radical (cations)4. Zero Group

4.1 Nessler’s reagent is :(A) K2 Hg4 (B) K2 Hg4 + KOH (C) K2Hg 2 + KOH (D) K2 Hg4 + K

4.2 Ammonia/ammonium ion gives yellow precipitate with :(A) H2PtCl6 (B) HgCl2 (C) Na3[Co(NO2)6] (D) (A) and (C) both

4.3 Ammonium salts on heating with slaked lime liberates a colourless gas (X). Identify the correct statement forgas (X).(A) (X) turns red litmus blue and produces dense white fumes in contact with dilute HCl.(B) (X) turns filter paper moistened with mercurous nitrate black and gives intense blue coloured solution with

CuSO4(aq).(C) (X) when passed through Nessler's reagent produces a brown colour precipitate.(D) All of these.

5. Ist Group5.1 A metal nitrate reacts with KI solution to give yellow precipitate which on addition of excess of more

concentrated solution (6 M) of KI dissolves forming a solution. The cation of metal nitrate is :(A) Hg2

2+ (B) Ag+ (C) Pb2+ (D) Cu2+

5.2 Three separate samples of a solution of a single salt gave these results. One formed a white precipitate withexcess ammonia solution, one formed a white precipitate with dilute NaCl solution and one formed a blackprecipitate with H2S. The salt could be :(A) AgNO3 (B) Pb(NO3)2 (C) Hg(NO3)2 (D) Mn(NO3)2

5.3* White precipitate of silver chloride is soluble in :(A) KCN solution (excess) (B) sodium thiosulphate solution (excess)(C) ammonia solution (D) concentrated solution of KCl

5.4 Cu2+ and Ag+ are both present in the same solution . To precipitate one of the ions and leaves the other insolution, add :(A) H2S (aq) (B) HCl (aq) (C) HNO3(aq) (D) NH4NO3(aq)

5.5 Consider the following observation :Mn+ + HCl (dilute) white precipitate water soluble

–24CrO yellow precipitate.

The metal ion Mn+ will be :(A) Hg2+ (B) Ag+ (C) Pb2+ (D) Sn2+

5.6* In which of the following reactions, white precipitate is obtained as one of the reaction products ?(A) Pb2+ (aq) + CO3

2– (aq) + H2O () Products(B) Pb2+ (aq) + Br– (aq) Products(C) Ag+ (aq) + NH3 (aq) + H2O () Productss(D) Ag+ (aq) + Cl– (aq) Productss

5.7 A white crystalline substance dissolves in water. On passing H2S in this solution, a black precipitate isobtained. The black precipitate dissolves completely in hot HNO3. On adding a few drops of concentratedH2SO4 , a white precipitate is obtained. This precipitate is that of :(A) BaSO4 (B) SrSO4 (C) PbSO4 (D) CdSO4





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6. IInd Group6.1 Sometimes yellow turbidity appears while passing H2S gas even in slightly acidic medium the absence of

group radicals. This is because :(A) sulphur is present in the mixture as impurity.(B) IV group radicals are precipitated as sulphides.(C) of the oxidation of H2S gas by some acid radicals.(D) group radicals are precipitated as hydroxides.

6.2 H2S in the presence of HCl precipitates group but not V group because :(A) HCl activates H2S (B) HCl increases concentration of Cl–

(C) HCl decreases concentration of S2– (D) HCl lowers the solubility of H2S in solution

6.3 Yellow ammonium sulphide solution is a suitable reagent for the separation of :(A) HgS and PbS (B) PbS and Bi2 S3 (C) Bi2 S3 and CuS (D) CdS and As2 S3

6.4 In which of the following pairs the precipitates are red and black coloured respectively and both precipitatesare soluble in excess KI solution ?(A) HgI2 , Hg2I2 (B) HgI2 , BiI3 (C) Cu2I2 , AgI (D) CdI2 , PbI2

6.5 Which one of the following salts will produce clear and transparent original solution in 2M HCl ?(A) Ag2CO3 (B) Pb(CO3)2 (C) Hg2CO3 (D) CuCO3

6.6 A metal chloride original solution (i.e. O.S) on mixing with K2CrO4 solution gives a yellow precipitate solublein aqueous sodium hydroxide. The metal may be :(A) mercury (B) iron (C) silver (D) lead

6.7 Which of the following is insoluble in dil. HNO3 but dissolves in aquaregia ?(A) HgS (B) PbS (C) Bi2 S3 (D) CuS

6.8 When small amount of SnCl2 is added to a solution of Hg2+ ions, a silky while precipitate is obtained. Thesilky white precipitate is due to the formation of :(A) Hg2Cl2 (B) SnCl4 (C) Sn (D) Hg

6.9 Which of the following reagents gives white precipitate with Hg(NO3)2 solution ?(A) Cobalt (II) thiocyanate (B) Tin (II) chloride (excess)(C) Ammonia solution (D) Potassium cyanide solution

6.10 When excess of dilute NH4OH is added to an aqueous solution of copper sulphate an intense blue colour isdeveloped. This is due to the formation of :(A) [Cu(NH3)6]2+ (B) Cu(OH)2 (C) [Cu(NH3)4]2+ (D) (NH4)2SO4

6.11 A black sulphide is formed by the action of H2S on :(A) cupric chloride (B) cadmium chloride (C) zinc chloride (D) ferric chloride.

6.12* Cu2+ ions will be reduced to Cu+ ions by the addition of an aqueous solution of :(A) KI (B) KCl (C) KSCN (D) KCN

6.13 When bismuth chloride is poured into a large volume of water the white precipitate produced is of :(A) BiO.OH (B) Bi2 O3 (C) BiOCl (D) Bi (OH)3

6.14* Which of the following is/are not correctly matched ?(A) BiI3 Black (B) Cu2I2 White precipitate(C) PbI2 Yellow precipitate (D) HgI2 Red precipitate





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7. IIIrd Group

7.1 When NH4Cl is added to a solution of NH4OH :(A) the dissociation of NH4OH increases. (B) the concentration of OH– increases.(C) the concentrations of both OH– an NH4

+ increase. (D) the concentration of OH– ion decreases.

7.2 The solution of sodium meta aluminate on diluting with water and then boiling with ammonium chloride gives:(A) [Al(H2O)5OH]2+ (B) AlCl3 (C) Al (OH)3 (D) NaAl(OH)4

7.3 An original solution of an inorganic salt in dilute HCl gives a brown colouration with potassium hexacyanidoferrate(III) and reddish brown colouration with sodium acetate solution. The cation of the salt is :(A) Ni2+ (B) Fe3+ (C) Cu2+ (D) none

7.4 Intense blue precipitate of Fe4[Fe(CN)6]3 and potassium hydroxide solution when mixed gives :(A) K2Fe[Fe(CN)6] - white precipitate (B) Fe(OH)3 - reddish–brown precipitate(C) Fe(CN)3 – reddish–brown precipitate (D) KFe[Fe(CN)6] - Turnbull's blue

7.5 Turnbull’s blue is a .................... .(A) ferricyanide (B) ferrous ferricyanide (C) ferrous cyanide (D) ferri ferrocyanide

7.6 Fe(OH)3 and Cr(OH)3 precipitates can be completely separated by :(A) Aq. NH3 (B) HCl (C) NaOH/H2O2 (D) H2SO4

7.7 Ferric alum gives deep red colour with NH4SCN due to the formation of :(A) Al(SCN)3 (B) [Fe(SCN)3]– (C) Fe(SCN)3 (D) none of these.

7.8 NH4SCN can be used to test one or more out of Fe3+ , Co2+ ,Cu2+ :(A) Fe3+ only (B) Co2+ , Cu2+ only (C) Fe3+ Cu2+ only (D) All

7.9 K4[Fe(CN)6] can be used to detect one or more out of Fe2+ , Fe3+, Zn2+, Cu2+, Ag+ , Ca2+ :(A) only Fe2+, Fe3+ (B) only Fe3+,Zn2+,Cu2+ (C) all but not Ca2+ (D) all of these.

8. IVth Group8.1 To increase significantly the concentration of free Zn2+ ion in a solution of the complex ion [Zn(NH3)4]2+

Zn2+ (aq) + 4NH 3 (aq) [Zn(NH3)4]2+ (aq)add to the solution some :(A) H2O (B) HCl (aq) (C) NH3(aq) (D) NH4Cl (aq)

8.2 CoS (black) obtained in group IV of salt analysis is dissolved in aqua regia and is treated with an excess ofNaHCO3 and then Br2 water. An apple green coloured stable complex is formed. It is :(A) sodium cobaltocarbonate (B) sodium cobaltibromide(C) sodium cobalticarbonate (D) sodium cobaltobromide

8.3 A metal salt solution when treated with dimethyl glyoxime and NH4OH gives a rose red complex. The metalis:(A) Ni (B) Zn (C) Co (D) Mn.

8.4 An aqueous solution of colourless metal sulphate M, gives a white precipitate with NH4OH. This was solublein excess of NH4OH. On passing H2S through this solution a white precipitate is formed. The metal M in thesalt is :(A) Ca (B) Ba (C) Al (D) Zn

8.5 Which one of the following ions does not give borax bead test ?(A) Cr3+ (B) Cu2+ (C) Mn2+ (D) Zn2+





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8.6 Which of the following compound is formed in borax bead test ?(A) Orthoborate (B) Metaborate (C) Double oxide (D) Tetraborate

8.7* White precipitate of Zn(OH)2 dissolves in :(A) sodium hydroxide solution (B) acid solution(C) ammonia solution (D) solution of ammonium salts

8.8* Select the correct statements with respect to the manganese nitrate solution in water.(A) It gives pink precipitate of Mn(NH4)PO4.7H2O with Na2HPO4, in the presence of ammonia solution.(B) It gives white precipitate of Mn(OH)2 with sodium hydroxide which rapidly oxidises on exposure to air,becoming brown.(C) On boiling with PbO2 and concentrated HNO3, a violet-red coloured product is obtained.(D) It gives white precipitate of manganese(II) sulphide with ammonium sulphide solution.

9. Vth and VIth Group9.1 Aqueous Solution of BaBr2 gives yellow precipitate with :

(A) K2CrO4 (B) AgNO3 (C) (CH3COO)2Pb (D) (A) and (B) both

9.2 The addition of K2CO3 (aq) to the following solution is expected to produce a precipitate in every case butthat one which does not produce precipitate is :(A) BaCl2(aq) (B) CaBr2(aq) (C) Na2SO4(aq) (D) Pb(NO3)2 (aq)

9.3 An aqueous solution of salt gives white precipitate with AgNO3 solution as well as with dilute H2SO4. It maybe:(A) Pb(NO3)2 (B) Ba(NO3)2 (C) BaCl2 (D) CuCl2

9.4 If crimson flame is given when an inorganic mixture is tested by flame test, it may be due to the presence of:(A) potassium (B) strontium (C) barium (D) calcium

9.5 A brick red colour is imparted to Bunsen flame by a :(A) Ca salt (B) Sr salt (C) Na salt (D) Co salt

9.6 The presence of magnesium is confirmed in the qualitative analysis by :(A) titan yellow solution + 2M NaOH solution (B) disodium hydrogen phosphate +NH4Cl + NH3 (aq.)(C) magneson(I) reagent (D) all of these

9.7* Which of the following solutions give white precipitate with Pb(NO3)2 as well as with Ba(NO3)2 ?(A) Sodium chloride (B) Sodium sulphate(C) Disodium hydrogen phosphite (D) Sodium chromate

9.8 Mg is not precipitated in V group because :(A) MgCO3 is soluble in water. (B) Ksp of MgCO3 is high.(C) MgCO3 is soluble in NH4OH. (D) None.





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PART-I : OBJECTIVE QUESTIONS

Single Correct Answer Type

1. When H2S is passed through an ammonical salt solution X, a white precipitate is obtained. Then Xcan be a :(A) Co2+ solution (B) Mn2+ solution (C) Ni2+ solution (D) Zn2+ solution

2. In third group, bromine water is used to test :(A) Fe3+ ions (B) Cr3+ ions (C) Al3+ ions (D) All of these

3. In IV group analysis NH4OH is added before passing H2S gas because :(A) The sulphides of IV group are insoluble in NH4OH(B) The sulphides of other metals are soluble in NH4OH(C) The concentration of S2- ions is increased(D) The sulphides of second group are soluble in NH4OH

4. An aq. solution containing Hg22 ; Hg2+, Pb2+ and Cd2+ ions is mixed with dil. HCl. Which will be

precipitated ?(A) Hg2Cl2 (B) PbCl2 (C) Both (A) and (B) (D) None of these

5. Disodium hydrogen phoshate is used to test :(A) Mg2+ (B) Na+ (C) Ca2+ (D) All

6. An inorganic salt solution on treatment with HCl gives a white precipitate of which metal ions ?

(A) Hg 22 (B) Hg2+ (C) Zn2+ (D) Cd2+

7. An inorganic salt solution gives a yellow preceipte with silver nitrate. The precipitate dissolves in dilutenitric acid as well as in ammonium hydroxide. The solution contains :(A) bromide (B) iodide (C) phosphate (D) chromate

8. Which of the following salts will turn water coloured when fumes evolved on treatment with conc.H2SO4 are passed in water ?(A) Nitrate (B) Bromide (C) Both (D) None

9. A salt which gives CO2 with hot conc. H2SO4 and also decolourizes acidified KMnO4 on warming is:(A) bicarbonate (B) carbonate (C) oxalate (D) acetate

10. Na2CO3 cannot be used in place of (NH4)2 CO3 for the precipitation of V group, because :(A) Na+ interferes in the detection of V group. (B) conc.of CO3

2– is very low.(C) Na will react with acid radicals. (D) Mg will be precipitated.

11. Which gives blood red colour with ammonium thiocyanate ?(A) Fe3+ (B) Fe2+ (C) Cu2+ (D) Cd2+

12. In III group precipitation NH4Cl is added before adding NH4OH due to :(A) decreasing conc. of OH– (B) prevent interference of PO4

3–

(C) increase in conc. of Cl– (D) increase in conc. of OH– ions

13. Few drops of HNO3 are added to II group filtrate before proceeding to III group in order to :(A) convert Fe2+ to Fe3+ (B) convert Fe3+ to Fe2+

(C) precipitate III group (D) none





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14. The sulphides of which one of the following groups of elements are soluble in yellow ammoniumsulphide?(A) As, Sb and Sn (B) As, Cd and Sn (C) Cd, Cu and Bi (D) Hg, Cu and Cd

15. How do we differentiate between Fe3+ and Cr3+ in group III ?(A) By adding excess of NH4OH solution. (B) By increasing NH4

+ ion concentration.(C) By decreasing OH– ion concentration. (D) Both (B) and (C).

16. salt X Heat

NaOH Y (gas)

Gives brown (Mg3N2 + H2O)ring testSalt X is :(A) NH4NO3 (B) NH4Cl (C) KNO3 (D) Ba(NO3)2

17. (KCl + K Cr O + H SO )2 2 7 2 4Heat Red Gas

dil NaOHYellowSolution

Pb(Ac)2X

The formula and colour of X are respectively :(A) CrO2Cl2, red colour(B) PbCrO4, yellow colour(C) BaCrO4, Green Colour(D) Cr2(SO4)3, Green Colour

18. A substance on treatment with dil H2SO4 liberates a colourless gas which produces :(i) turbidity with baryta water and(ii) turns acidified dichromate solution greenThe reaction indicates the presence of :(A) CO3

–2 (B) S–2 (C) SO3–2 (D) NO2

–

19.

The gas ‘G’ will show which of the following property ?(A) It turns lead acetate filter paper black.(B) It turns acidified K2Cr2O7 filter paper green.(C) It produces purple colouration on filter paper moistened with sodium nitroprusside already made alkalinewith sodium hydroxide.(D) All of these





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20. Consider following reaction ; Nitrite + Acetic acid + Thiourea N2 + SCN– + 2H2O. Formation of theproduct in the above reaction can be identified by :(A) FeCl3 / dilute HCl, when blood red colour appears.(B) FeCl3 / dilute HCl, when blue colour appears.(C) K2Cr2O7 / HCl, when green colour appear.(D) KMnO4

/ HCl, when colourless solution is formed.

21. White precipitate of AgCl turns to greyish or black when :(A) reacts with Na3AsO4 (B) exposed to sunlight(C) reacts with K2CrO4 (D) reacts with concentrated HCl

22. A mixture of two colourless substances was dissolved in water. When gaseous Cl2 was passed through thesolution, containing small quantity of CCl4 a violet colour developed in organic layer. Addition of BaCl2 to theoriginal solution give a white precipitate. The mixture contains :(A) salts of nitrate and chloride. (B) salts of bromide and chloride.(C) salts of iodide and sulphate. (D) salts of sulphate and chloride.

23. A white crystalline solid (A) on boiling with caustic soda solution gave a gas (B), which when passed throughan alkaline solution of potassium mercuric iodide gave brown precipitate. The substance (A) on heating gavea gas (X), which rekindled a glowing splinter but did not give brown fumes with nitric oxide .The gas (B) is :(A) H2 S (B) NH3 (C) HCl (D) CO2

24. An aqueous solution of compound 'A' gives white precipitate with 2M HCl. The precipitate becomes black onaddition of aqueous NH3 due to formation of ‘B’. ‘B’ dissolves in aquaregia. ‘A’ and ‘B’ are :(A) Hg2+ and Hg Cl2 (B) Hg2

2+ and Hg2 Cl2(C) Hg2+ and Hg (NH2) Cl + Hg (D) Hg2

2+ and Hg (NH2) Cl + Hg

25. A compound (X) reacts in the following ways.

The compound (X) is likely to be(A) Pb(NO3)2 (B) CaCrO4 (C) Hg(NO3)2 (D) AgNO3

26. To a solution of a substance, gradual addition of ammonium hydroxide results in a brownish blackprecipitate which does not dissolve in excess of NH4OH. However, when KI (not in excess) is added to theoriginal solution, a green precipitate is formed. The solution contained :(A) lead salt (B) silver salt (C) mercurous salt (D) copper salt

27. Black precipitate of copper sulphide dissolves in :(A) KCN solution. (B) sodium sulphide solution.(C) sodium hydroxide. (D) boiling dilute (M) sulphuric acid.

28. Which of the following metal salts gives a red and opaque borax bead in the reducing flame (in cold) ?(A) Ni (B) Fe (C) Cu (D) Mn

29. Which one among the following pairs of ions cannot be separated by H2S in dilute hydrochloric acid ?(A) Bi3+, Sn4+ (B) Al3+, Hg2+ (C) Zn2+, Cu2+ (D) Ni2+, Cu2+

30. The reagents, NH4Cl and aqueous NH3 will precipitate :(A) Ca2+ (B) Al3+ (C) Mg2+ (D) Zn2+ .





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31. In the precipitation of the iron group in qualitative analysis, ammonium chloride is added before addingammonium hydroxide to :(A) decrease concentration of OH– ions (B) prevent interference by phosphate ions(C) increase concentration of Cl– ions (D) increase concentration of NH4

+ ions

32. Which one of the following can be used in place of NH4Cl for the identification of the third group radicals?(A) NH4NO3 (B) (NH4)2SO4 (C) (NH4)2CO3 (D) NaCl.

33. Which one of the following metal salts produces a blue coloured bead in cobalt nitrate charcoal cavity test ?(A) Zn2+ (B) Mg2+ (C) Sn2+ (D) Al3+

34. Which of the following is correct ?(A) AgCl(s) + Na3 AsO3 colourless solution (B) FeCl3(aq) + K4 Fe(CN)6 brown precipitate.(C) FeCl3(aq) + K3Fe(CN)6 brown colouration. (D) CuSO4(aq) + KCN (excess) blue colouration.

35. Fe2+ does not give prussian blue colour with K4[Fe(CN)6] but on its reaction with (X), prussian blue colourappears. (X) can be :(A) MnO4

–/ H+ (B) Zn/NaOH (C) NH3 (aq) (D) all true

36. When HNO3 is added to sodium ferrocyanide, which of the following observation is observed ?(A) NaFe[Fe(CN)6] is produced. (B) Fe4[Fe(CN)6]3 is formed.(C) Fe3[Fe(CN)6]2 is formed. (D) Na2[Fe(CN)5(NO)+]2– is formed.

37. What product is formed by mixing the solution of K4 [Fe(CN)6] with the solution of FeCl2 in completeabsence of air ?(A) Ferro ferricyanide (B) Ferric ferrocyanide (C) Ferric ferricyanide (D) None

38. Select the correct statement with respect to Fe3+ ions.(A) Iron (III) ions react with H2S in acidic solution to give a black precipitate of Fe2S3.(B) Iron (III) ions react with ammonium sulphide to give the black precipitate of Fe2S3.(C) Iron (III) ions react with ammonium thiocyanate solution to produce deep red colouration.(D) All of these

39. Which one of the following compounds on reaction with Na2O2 in alkaline medium gives yellow coloursolution?(A) Cr (OH)3 (B) Zn(OH)2 (C) Al(OH)3 (D) None of these.

40. A dark green bead in the borax bead test (in oxidising flame) indicates the presence of :(A) Cr3+ (B) Mn2+ (C) Co2+ (D) Ni2+

41. Which of the following cation does not give red colour precipitate/solution with dimethylglyoxime (DMG) inalkaline solution ?(A) Zn+2 (B) Ni+2 (C) Fe2+ (D) both (A) and (C)

42. A suspension containing insoluble substances ZnS, MnS, HgS, Ag2S and FeS, is treated with 2N HCl. Onfiltering, the filtrate contains appreciable amounts of which one of the following?(A) Zinc and mercury (B) Silver and iron(C) Manganese and mercury (D) Zinc, manganese and iron

43. An aqueous solution contains both Al3+ & Zn2+.To this solution NH4OH is added in excess.(A) Only Al(OH)3 will be precipitated. (B) Only Zn(OH)2 will be precipitated.(C) Both will be precipitated. (D) No precipitate will appear.

44. A metal M and its compound can give the following observable changes in a sequence of reactions,

M3HNO

dilutevery

evolvedisgasnoandsolutionColourless

NaOHaqueous

eprecipitatWhite

.)aq(NaOHexcess

solutionColourless

–

2 OH/SH

eprecipitatWhite

The metal M can be :(A) Mg (B) Pb (C) Zn (D) Sn





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45. In fifth group, (NH4)2CO3 is added to precipitate out the carbonates. We do not add Na2CO3 because :(A) CaCO3 is soluble in Na2CO3.(B) Na2CO3 increases the solubility of fifth group carbonates.(C) MgCO3 will be precipitated out in fifth group.(D) none.

46. A metal salt solution forms a yellow precipitate with potassium chromate in acetic acid, a white precipitatewith dilute sulphuric acid, but gives no precipitate with sodium chloride or iodide, it is :(A) lead carbonate (B) basic lead carbonate(C) barium carbonate (D) strontium carbonate

Multiple Correct Answer(s) Type :

47. Cu2+ ions give white precipitate with :(A) potassium iodide solution. (B) potassium thiocyanate and saturated solution of SO2.(C) excess potassium cyanide solution. (D) potassium hydroxide solution.

48. Which of the following statements is/are true ?(A) Ag+ ions do not give white precipitate with concentrated HCl.(B) Cu2+ ions produce a white precipitate when KCN solution is added in a small quantity.(C) Hg2+ ions give deep blue precipitate with cobalt acetate and ammonium thiocyanate.(D) Black precipitate of BiI3 turns orange when heated with water.

49. Na2SO4 and Na2S can be distinguished from each other by using :(A) dilute H2SO4 (B) acidified KMnO4 solution(C) sodium nitroprusside solution (D) cadmium acetate solution

50. K solution is the reagent for :(A) Hg2+ (B) Pb2+ (C) Ag+ (D) Cu2+

51. Which of the following cations form(s) black precipitate(s) with H2S (g) ?(A) Cu2+ (B) Sb3+ (C) Pb2+ (D) Bi3+

52. In B group of basic radicals, the yellow precipitate (s) is/are given by :(A) As3+ (B) Sb3+ (C) Sn4+ (D) Sn2+

53. Borax bead test is given by :(A) Co2+ (B) Zn2+ (C) Cu2+ (D) Ni2+

54. Which of the following anion(s) evolve(s) reddish brown gas with concentrated H2SO4?(A) Br– (B) NO3

– (C) SO32– (D) –

55. Concentrated aqueous ammonia dissolve(s) which of the following completely ?(A) AgCl (B) AgBr (C) Ag2CrO4 (D) Ag

56. Hg2I2 (green) OHwith

boiled

2

products

Which of the following statement is correct with respect to the products ?(A) Black precipitate of mercury(I) oxide is formed. (B) Violet colour gas is evolved.(C) Red precipitate of HgI2 is formed. (D) Mercury is obtained

57. H2S will precipitate the sulphide of all the metals from the solution of chlorides of Cu, Zn and Cd if :(A) the solution is aqueous. (B) the solution is acidic.(C) the solution is slightly acidic. (D) solution is alkaline.





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58. Which of the following statement(s) is /are false ?(A) Fe3+ gives red precipitate with dimethyl glyoxime in alkaline solution.(B) Cu2+ ion with potassium iodide solution gives a dirty brownish white precipitate which turns white onadding hypo solution.(C) A filter paper soaked in mercurous nitrate turns black in contact with ammonia gas.(D) Ag2O does not dissolve in nitric acid and ammonia solution.

59. Which of the following compound(s) is /are insoluble in excess aqueous sodium hydroxide ?(A) ZnCl2 (B) CdCl2 (C) AlCl3 (D) MnCl2

60. Ammonium molybdate test is used for the estimation of :(A) PO4

3– (B) Mg2+ (C) As3+ (D) CH3COO–

61. Which of the following statement(s) is/are true?(A) Titan yellow solution gives red colouration with a neutral solution containing Mg2+ ions(B) Solution of nitrite is decomposed by sulphamic acid.(C) Fe2+ ions give brown colour precipitate with [Fe(CN)6]3– ions solution.(D) Green precipitate of Cr(OH)3 is soluble in Na2O2.

62. Which of the following is/are correct for potassium ferrocyanide ?(A) It gives a brown precipitate with Cu2+ ions.(B) It gives a white precipitate of mixed salt with Ca2+ ions.(C) It in excess gives a bluish white/white precipitate with Zn2+.(D) It develops a deep red colouration with Fe3+.

63. CoCl2 + KNO2 + CH3COOH [X] + H2O + KCl + CH3COOK + NO(Unbalenced equation)(A) X is a yellow crystalline solid insoluble in water.(B) X is a green coloured compounds knwon as kinman's green.(C) IUPAC name of X is potassium hexanitrito –N– cobaltate (II)(D) The compound X is an inner orbital complex.

64. Consider the reactions shown below ;

Which of the following statement (s) is/are correct ?(A) [X] is a yellow coloured precipitate.(B) [X] is soluble in ammonia solution.(C) [Y] gives green coloured solution with excess of sodium hydroxide solution.(D) The conversion of Cr2O7

2– to [Y] is an redox reaction.

PART-II SUBJECTIVE QUESTIONS

1. What will happen if to a solution of Ca(HCO3)2, formed by passing the carbon dioxide through a milkysolution of CaCO3 for a longer time, ammonia solution is added ?

2. Write the names of the acidic radicals which can be tested by aqueous solution of barium chloride.

3. What will happen if to a white precipitate of BaSO3 , bromine water is added ?





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4. A nitrite solution is added to a saturated solution of iron(II) acidified with dilute acetic acid or with dilutesulphuric acid. If any reactions occours then write the name and chemical composition of the productformed. Write also the chemical equations involved.

5. What happens when a sulphite reacts with dilute H2SO4 in presence of zinc ?

6. A compound containing acetate radical is made to react with neutral ferric chloride. The solution is thendiluted with water and boiled for 1-2 minutes. A reddish brown precipitate is obtained. Give the chemicalcomposition of reddish brown precipitate.

7. In which reagents the AgCl precipitate is soluble ?

8. In which of the following reagents, the white precipitate of PbSO4 is soluble ?dilute HCl, hot concentrated H2SO4, ammonium acetate (6M), ammonium tartrate 6M in the presence ofammonia, sodium hydroxide solution.

9. Mercuric nitrate solution reacts with a soluble sulphate forming a yellow precipitate. If the statement is truethen explain giving the complete balanced equation.

10. What is the formula of iodide of Millon's base ?

11. What happens when ammonia gas is passed into a solution of sodium cobaltinitrite ?

12. When calomel reacts with ammonia solution, a black precipitate is formed. Write the chemical equation andalso name the reaction nature.

13. What products are formed when precipitate formed by the reaction of Hg22+ ions and excess of sodium

hydroxide solution is boiled ?

14. In which of the reagent, white precipitate of Pb3(PO4)2 is soluble ?

15. Why do lead salts turn black on keeping for a long time in the laboratory ?

16. Name one chloride which is soluble in hot water as well as in excess of HCl.

17. Does mercuric sulphide dissolve in sodium sulphide solution (of 2M) ?

18. What happens when white precipitate of Bi(OH)3 is boiled ?

19. Why Na2S cannot be used in place of H2S (in presence of HCl) as a reagent for IInd group cations ?

20. Is their any reaction other then cyanide reaction which can be used for the differentiation of Cu2+ and Cd2+

ions?

21. Which basic radical is tested with the help of alkaline sodium stannite?

22. What happens when ammonium sulphide solution reacts with a solution containing a Cr(III) salt ?

23. Do Fe(III) salts and Fe(II) salts both give red colouration with dimethylglyoxime in ammonical solution. If notthen which iron salt gives red colouration with dimethylglyoxime ?

24. Which colour precipitate is formed by Fe(II) salt with potassium ferrocyanide, (i) in complete absence of airand (ii) under ordinary atmospheric condition ?

25. Partial precipitation of Mn2+ as Mn(OH)2 occurs with ammonia solution but the precipitate is soluble inammonium salts. Explain ?





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26. What happens when Mn(II) ions free from chloride ions react with acidified solution of (NH4)2S2O8 or K2S2O8in presence of a few drops of AgNO3 solution ?

27. Why Zn(II) salt is not precipitated as Zn(OH)2 by ammonia solution in the presence of excess of ammoniumchloride ?

28. What will happen if the precipitation of Vth group cation by ammonium carbonate is carried out in neutralmedium ?

29. What happens when ammonium sulphate solution is added to a solution containing both Sr2+ and Ca2+

ions?

30. Which colour precipitate is obtained when a solution of Ca2+ ions reacts with potassium ferrocyanide.

31. Salt + H2SO4 (dilute) Coloured vapours which turns starch iodide paper blue. Identify the acid radicaland the coloured vapours giving the relevant chemical equations.

32. Which chloride of st group basic radicals turns black on treatment with NH3 ?

33. Which basic radicals form oxo-cations in aqueous solutions ?

34. Which ions cannot co-exist in solution ?

35. Which radical of group IVth gives bluish white / white precipitate with excess K4[Fe(CN)6] ?

36. What products are formed ? When :(i) Disodium hydrogen phosphate is added to magnesium sulphate in presence of ammonium chloride andaqueous ammonia.(ii) A solution containing Zn2+ ions is poured in an aqueous ammonia.(iii) Bi(NO3)3 solution is mixed with K and then resulting precipitate is heated with water.(iv) Disodium hydrogen phosphate is boiled with concentrated HNO3 and ammonium molybdate reagent.

37. Complete and balance the following chemical reactions.

(i) Cu(BO2)2 + C fused (ii) AgBr + concentrated NH3

(iii) Cr(OH)3 + Na2CO3 + KNO3 fused (iv) Cu(NO3)2

(v) CaSO3 + SO2 + H2O

38. Complete and balance the following reaction.(i) Na2S + CdCO3 ............... + ..............

(ii) CoCl2 + NH4SCN Ether ............... + ...........

39. A black coloured compound (A) on reaction with dilute H2SO4 gives a gas (B) which on passing in a solutionof an acid (C) gives a white turbidity (D). Gas (B) when passed in an acidified solution of a compound (E)gives a precipitate (F) soluble in dilute HNO3. After boiling this solution when an excess of NH4OH is added,a intense blue coloured compound (G) is formed. To this solution on addition of acetic acid and aqueousK4[Fe(CN)6] a chocolate brown precipitate (H) is obtained. On addition of an aqueous solution of BaCl2 to anaqueous solution of (E) a white precipitate insoluble in dilute HCl is obtained. Identify the compounds from(A) to (H).





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40. A compound (A) is greenish crystalline salt, which gave the following reactions.(i) Addition of BaCl2 solution to the solution of (A) results in the formation of white precipitate (B) which isinsoluble in dilute HCl.(ii) On heating (A), water vapours and two oxides of sulphur (C) and (D) are liberated leaving a red brownresidue (E).(iii) (E) dissolves in warm concentrated HCl to give a yellow solution (F).(iv) Solution (F) on treatment with thiocyanate ions gives blood red coloured compound (G).Identify the compounds from (A) to (G).

41. An aqueous solution of salt (A) gives a white crystalline precipitate (B) with NaCl solution. The white precipitateturns black forming (C) when H2S gas is passed through it. Compound (B) dissolves in hot water and theresulting solution gives yellow precipitate (D) with KI or yellow precipitate with K2CrO4 or white precipitatewith dilute H2SO4 which is insoluble in C2H5OH. The compound (A) does not evolve any gas with dilute HClbut liberates a reddish brown gas on heating. Identify the compounds (A) to (D).

42. A white substance (A) reacts with dilute H2SO4 to produce a colourless gas (B) and a colourless solution(C). The reaction between (B) and acidified K2Cr2O7 solution produces a green solution and a slightlycoloured precipitate (D). The substance (D) burns in air to produce a gas (E) which reacts with (B) to yield (D)and a colourless liquid. Anhydrous copper sulphate is turned blue on addition of this colourless liquid.Addition of aqueous NH3 or NaOH to (C) produces first a white precipitate which dissolves in the excess ofthe respective reagent to produce a clear solution in each case. Identify (A), (B), (C), (D) and (E).

43. A mixture of two salts was treated as follows.(i) The mixture was heated with precipitated MnO2 and concentrated H2SO4 when a yellowish green gas was liberated.(ii) The mixture on heating with NaOH solution gave a gas which turned red litmus blue.(iii) Its solution in water gave red colouration with dimethylglyoxime in alkaline solution and white precipitatewith K4[Fe(CN)6] in absence of air.(iv) The mixture was boiled with KOH and the liberated gas was bubbled through an alkaline solution ofK2Hg4 to give a brown precipitate. Identify the ions present in the mixture.

44. (i) A yellow coloured precipitate of compound (A) is formed on passing H2S through a neutral solutionof a salt (B).

(ii) (A) is soluble in hot dilute HNO3 , but insoluble in yellow ammonium sulphide.(iii) The solution of (B) on treatment with small quantity of NH3 gives white precipitate which

becomes soluble in excess of it forming a compound (C).(iv) The solution of (B) gives white precipitate with small concentration of KCN which becomes soluble

in excess of this regent forming a compound (D).(v) The solution of (D) on treatment with H2S gives (A).(vi) The solution of (B) in dilute HCl on treatment with a solution of BaCl2 gives white precipitate of

compound (E) which is insoluble in concentrated HNO3.Identify compounds (A) to (E).

45. (i) An aqueous solution of a compound (A) is acidic towards litmus and (A) is sublimed at about 300ºC.(ii) (A) on treatment with an excess of NH4SCN gives a red coloured compound (B) and on treatment

with a solution of K4Fe(CN)6 gives a blue coloured compound (C).(iii) (A) on heating with excess of solid K2Cr2O7 in presence of concentrated H2SO4 gives deep red vapour

of (D).(iv) On passing vapour of (D) into a solution of NaOH and then adding the solution of acetic and lead

acetate, a yellow precipitate of compound (E) is obtained .Identify (A) to (E) and give chemical equations for the reactions at steps (ii) to (iv).

46. (i) A blue coloured compound (A) on heating gives two product (B) & (C).(ii) A metal (D) is deposited on passing hydrogen through heated (B).(iii) The solution of (B) in HCl on treatment with the [Fe(CN)6]4– gives a chocolate brown

coloured precipitate of compound (E).(iv) (C) turns lime water milky which disappears on continuous passage of (C) forming a

compound (F).Identify (A) to (F) and give chemical equations for the reactions at step (i) to (iv).





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47. (i) A black coloured compound (B) is formed on passing H2S through the solution of acompound (A) in NH4OH.

(ii) (B) on treatment with HCl and potassium chlorate or aquaregia gives (A).(iii) (A) on treatment with KCN gives a buff / reddish-brown coloured precipitate which dissolves in

excess of this reagent forming a compound (C).(iv) The compound (C) is changed into a compound (D) when its aqueous solution is boiled in air.(v) The solution of (A) was treated with excess of NaHCO3 & then with bromine water. On cooling &

shaking for some time, a green colour of compound (E) is formed. No change is observed on heating.Identify (A) to (E) and give chemical equations.

48. What happens when 4–nitrobenzene diazonium chloride reagent reacts with an ammonium salt in the presenceof sodium hydroxide solution ?

49. Why in cobalt nitrate test for aluminium salts, excess of cobalt nitrate should not be added ?

50. What happens when ?(a) To a Zn2+ ions solution faintly acidified with 2M acetic acid, 0.1 mL of 0.25 M CuSO4 solution and 2 mLof ammonium tetrathiocyanatomercurate(II) reagent is added.(b) The above test is performed in absence of CuSO4 solution.

1. MATCH THE COLUMN1.1 Match the colour of the precipitates with their respective compounds (molecular formula) obtained in the

analysis of different cations. Column Column (A) White crystalline precipitate (p) K3 [Co(NO2)6](B) Reddish brown precipitate (q) Cr(OH)3(C) Yellow precipitate (r) Fe(OH)3(D) Green precipitate (s) PbCl2

(t) Cu3[Fe(CN)6]2

1.2 Match the products of the reactions listed in column-I with the colour of the precipitate(s) listed in column-II.Column I Column II

(A) Hg2I2(green) OH

boiling

2

(p) Grey / Black precipitate

(B) BiI3(black) OH2

(q) Orange precipitate

(C) [Fe3(OH)2(CH3COO)6]+ (deep-red salt.) water

boiling (r) Reddish-brown precipitate

(D) Ag2SO3 (white) water

boiling (s) Red precipitate

(t) Green

1.3 Match the products of reactions listed in column-I with their characteristic(s) listed in column-II.Column I Column II

(A) HgI2 + I– (excess) (p) One of the products is a colourless soluble complex.

(B) Cr(OH)3 + NaOH (excess) (q) One of the products is a coloured soluble complex.

(C) PbCrO4 + NaOH (r) In one of the products the central atom or ion has tetrahedral geometry.

(D) K2Zn3[Fe(CN)6]2 + NaOH (s) One of the products is a paramagnetic complex.(t) One of the product is a diamagnetic complex.





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1.4 Column – I Column – II(Reagent) (Radical which gives any type of reactions ; precipitation,

complexation or redox reaction with reagent)(A) KCN (aq) (p) Pb2+

(B) NaOH (aq) (q) Ag+

(C) KI (aq) (r) Hg22+

(D) K2CrO4 (aq) (s) Cu2+

2. COMPREHENSION

Comprehension # 1A coloured solution known to contain two metal ions of different groups, was treated with excess cold sodiumhydroxide solution. When filtered a whitish solid, slowly changing to brown, was retained on the filter paperand a colourless solution collected as the filtrate. Drop wise addition of hydrochloric acid to the filtrateproduced a white precipitate which dissolved in excess acid. Treatment of the residue from the filter paperwith a strong oxidiser, PbO2 and concentrated HNO3 on boiling produced a reddish-violet (purple) solution.

2.1 Indicate any pairs of ions which on testing as above leads to the observed changes.(A) Al3+ and Mn2+ ions (B) Mg2+ and Zn2+ ions (C) Mn2+ and Mg2+ ions (D) Zn2+ and Mn2+ ions

2.2 Filtrate obtained after separation of white solid contains:(A) [Al(OH)4]– (B) Al2O3 (C) MnO (D) Na2MnO2

2.3 White solid changing to brown is due to formation of :(A) Mn(OH)2 (B) MgO (C) Al(OH)3 (D) MnO(OH)2

2.4 Reddish-violet solution obtained by oxidation is of :

(A) 22ZnO (B) MnO 2

4 (C) MnO 4 (D) MnO2

2.5 Reddish-violet (purple) solution is decolourised by :(A) both SO3

2–, Fe2+ (B) both SO42–, Fe3+ (C) both NO3

–, Fe2+ (D) both H2O2 , HCO32–

Comprehension # 2A chemist opened a cupboard and found four bottles containing water solutions, each of which had lost itslabel. Bottles 1, 2, 3 contained colourless solutions, while bottle 4 contained a blue solution. The labels fromthe bottles were lying scattered on the floor of the cupboard. They were :

copper (II) sulphate, hydrochloric acidlead nitrate, sodium carbonate

By mixing samples of the contents of the bottles, in pairs, the chemist made the following observations :

Bottle 1 + Bottle 2 white precipitate is formed.



Bottle 2 + Bottle 3 colourless and odourless gas is evolved

Bottle 2 + Bottle 4 no visible reaction is observed.

Bottle 3 + Bottle 4 blue precipitate is formed.With the help of the above observations answer the following questions.

2.6 Bottle 3 contains :(A) copper (II) sulphate (B) hydrochloric acid (C) lead nitrate (D) sodium carbonate





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2.7 Which of the following statements is correct for salts contained in bottle 1 and 4?(A) Bottle 4 gives white precipitate with excess of KI solution.(B) Bottle 4 gives white precipitate with excess of K4 [Fe (CN)6] solution.(C) Bottle 1 and 4 both gives precipitate with excess of NaOH solution.(D) Bottle 1 gives white precipitate with concentrated HCl solution.

2.8 Which one of the following bottles develops intensive deep blue colour with aqueous ammonia ?(A) Bottle 1 (B) Bottle 2 (C) Bottle 3 (D) Bottle 4

2.9 Which of the following bottle will give white precipitate with bottle 1?(A) Bottle 2 (B) Bottle 3 (C) Bottle 4 (D) All of these

Comprehension # 3Fe3+ ions in an aqueous solution gives deep red colouration with both sodium acetate (in excess) andammonium thiocyanate (slightly acidic).The deep red colouration obtained with ammonium thiocyanate gets decolourised on addition of a solutioncontaining F– ions.

2.10 The deep red colouration is due to the formation of :(A) Fe(CH3COO)2 (B) Fe(OH)2CH3COO(C) [Fe3(OH)2CH3COO)6]+ (D) [Fe3(CH3COO)6]

2.11 Which one of the following statements is false with respect to deep red colouration produced with NH4SCN?(A) The deep red colour is bleached by Hg(II) ions.(B) The deep red colouration is due to the formation of a non-dissociated iron(III) thiocyanate complex.(C) The deep red coloured compound can be extracted by ether or amyl alcohol.(D) None.

2.12 Select the correct statement with respect to the compound formed as a result of the bleaching of deep redcolouration of Fe(SCN)3 by a solution containing F– ions.(A) The net crystal field stabilisation energy is zero. (B) Central ion has sp3d2 hybridisation.(C) The compound is highly paramagnetic in nature. (D) All of these

2.13 Excess of sodium acetate is added in the reaction with Fe3+ ions because :(A) it acts as a buffer to control pH of the reaction other wise reaction is made reversible.(B) it makes the solution strong alkaline which destroys acidic effect if any.(C) it makes the solution acidic which destroys alkaline effect if any.(D) None

2.14 What happens when deep red coloured solution of [Fe3(OH)2(CH3COO)6]+ is diluted with water and thenboiled?(A) A deep red solution of ferric acetate is obtained.(B) A reddish-brown precipitate of basic ferric acetate is obtained.(C) A deep red precipitate of ferric hydroxide is obtained.(D) A yellow colour precipitate of a complex [Fe(CH3COO)6]3– is obtained.

3. ASSERTION / REASONINGAssertion and Reasoning :DIRECTIONS :

Each question has 5 choices (A), (B), (C), (D) and (E) out of which ONLY ONE is correct.(A) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1.(B) Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1.(C) Statement-1 is True, Statement-2 is False.(D) Statement-1 is False, Statement-2 is True.(E) Statement-1 and Statement-2 both are False.





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3.1 Statement-1 : Only nitrite is decomposed when treated with urea acidified with sulphamic acid in cold, in amixture of nitrite and nitrate.Statement-2 : NO2

– interferes in the brown ring test of NO3–.

3.2 Statement-1 : In a mixture containing Br– and – , violet colour (of2) appears first in chloroform layer, whenchlorine gas is passed through the mixture dissolved in water.Statement-2 : The order of the strength of reducing properties is as follows – >Br– > Cl– > F–.

3.3 Statement-1 : Orthophosphate gives yellow precipitate with silver nitrate solution.Statement-2 : Metaphosphate gives white precipitate with silver nitrate.

3.4 Statement-1 : PbCl2 and AgCl precipitates can be separated by ammonia solution.Statement-2 : PbCl2 precipitate is soluble in hot water and concentrated potassium chloride solution.

3.5 Statement-1 : Hg2Cl2 is blackened by NH3 due to the formation of iodide of Millon's base.Statement-2 : Hg2+ ions give deep-red crystalline precipitate with cobalt(II) thiocyanate.

3.6 Statement-1 : Unexposed silver nitrate of a photographic plate is removed by treatment with hypo solution.Statement-2 : Na5[Ag(S2O3)3] is a soluble complex.

3.7 Statement-1 : Barium bromide gives same colour precipitate with AgNO3 as well as with K2CrO4.Statement-2 : Silver bromide is completely soluble in dilute solution of ammonia.

3.8 Statement-1 : Aqueous solution of Pb2+ ions gives white precipitate with sodium carbonate solution.Statement-2 : A mixture of lead carbonate and lead hydroxide is formed.

3.9 Statement-1 : White precipitates of AgCl and PbCl2 can be separated by concentrated hydrochloric acid.Statement-2 : White precipitate of AgCl dissolves in concentrated hydrochloric acid.

3.10 Statement-1 : Cu2+ and Cd2+ ions react with KCN solution (in excess) forming the colourless solublecomplexes.Statement-2 : Of these colourless soluble complexes only cadmium complex gives yellow precipitate withH2S gas in slightly acidic medium.

3.11 Statement-1 : Aqueous solution containing sodium acetate and ferric chloride, when diluted with water andboiled gives brownish-red precipitate.Statement-2 : Basic iron (III) acetate is formed.

3.12 Statement-1 : Baryta water becomes turbid on passing CO2 gas through it but turbidity becomes clear onpassing more CO2 gas.Statement-2 : Carbonates give yellowish white precipitate with silver nitrate solution. The precipitate becomesyellow or brown on heating.

3.13 Statement-1 : A solution containing S2– ions gives purple / violet colour with sodium nitroprusside solutionin alkaline medium.Statement-2 : Sodium sulphide gives black precipitate with silver nitrate solution.

3.14 Statement-1 : Acidified K2Cr2O7 solution becomes green when SO2 gas is passed through it.Statement-2 : This is an redox reaction.

3.15 Statement-1 : White crystalline precipitate of silver sulphite dissolves, if sulphite ions are added in excess.Statement-2 : Sulphite ions decolourise the pink colour of acidified KMnO4.

3.16 Statement-1 : Nessler’s reagent gives a brown precipitate with aqueous ammonia as well as with ammoniumsalts.Statement-2 : Aqueous ammonia gives a brown precipitate with a solution of manganese (II) chloride andhydrogen peroxide.





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3.17 Statement-1 : No yellow precipitate is formed when an excess of a more concentrated (6M) solution of KI isadded to a solution containing Pb2+ ions.Statement-2 : Solution of [PbI4]2– on dilution with water produces yellow precipitate of PbI2.

3.18 Statement-1 : Cu2+ and Cd2+ ions form complexes with excess of potassium cyanide solution.Statement-2 : On passing H2S gas, complex [Cu(CN)4]2– is not effected but [Cd(CN)4]2– gives yellowprecipitate.

3.19 Statement-1 : A solution of BiCl3 in concentrated HCl when diluted with water gives white precipitate.Statement-2 : BiCl3 forms insoluble BiO+Cl– when diluted with a large quantity of water.

3.20 Statement-1 : When H2S gas is passed into an aqueous solution of ZnCl2 , Zn2+ ions are completelyprecipitated as zinc sulphideStatement-2 : Zinc sulphide is soluble in solutions of caustic alkali as well as in dilute HCl.

3.21 Statement-1 : An original solution containing excess of Ni2+ ions gives a yellow coloured solution withpotassium cyanide solution.Statement-2 : A solution of Ni2+ ions gives red precipitate with dimethylglyoxime solution just made alkalinewith ammonia.

4. TRUE / FALSE

4.1 Consider the following statements,S1 : Hg2Cl2 precipitate undergoes disproportionation with ammonia solution.S2 : Hg2l2precipitate with excess I– ions undergoes disproportionation.S3 : bismuth salt solution (chlorides or nitrates) produces a white precipitate when water is added to it inlarger volume.S4 : white precipitate of Cu(I) iodide produced by the reaction of CuSO4 and KI is intensely brown becauseof the formation of tri-iodide ions.and arrange in the order of true / false.(A) T F T T (B) T T F F (C) T T T T (D) T F T F

4.2 Consider the following statements,S1 : Fe(OH)3 and Cr(OH)3 precipitates can be separated using NaOH + H2O2 but not by excess of NaOHalone.S2 : Ag2CrO4 precipitate is soluble in dilute HNO3 and ammonia solution.S3 : both HgI2and BiI3precipitates form colourless soluble complexes with excess of potassium iodide solution.S4 : white precipitate of PbCl2 is turned black by H2S (not taken in excess) in saturated solution of KCl.and arrange in the order of true / false.(A) T F T T (B) F T F F (C) T T T T (D) T F T F

4.3 Consider the following statements,S1 : zinc hydroxide is soluble in sodium hydroxide but not in ammonia solution.S2 : Cd(OH)2 is soluble in sodium hydroxide as well as in ammonia solution.S3 : Cu2+ ions like Fe3+ ions give deep red colouration with SCN– ions.S4 : Fe2+ ions give red colouration with dimethylglyoxime in ammonical solution.and arrange in the order of true / false.(A) T F T T (B) F F F T (C) T T T T (D) T F T F

4.4 Consider the following statements,S1 : precipitate of lead thiosulphate is soluble in excess sodium thiosulphate (Na2S2O3).S2 : moderately concentrated solution of Ba2+ ions gives white precipitate of BaS2O3 with hypo.S3 : white precipitate of CaSO3 dissolves when excess of SO2 gas is passed through it.

S4 : Hg2+ + S2O32– + H2O HgS + SO4

2– + 2H+

and arrange in the order of true / false.(A) T F T T (B) T T F F (C) T T T T (D) T F T F





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4.5 Consider the following statements,S1 : yellow precipitate of SrCrO4 is soluble in large quantity of water.S2 : yellow precipitate of BaCrO4 is insoluble in dilute acetic acid.S3 : yellow precipitate of PbCrO4 is not soluble in sodium hydroxide.S4 : white precipitate of Pb(CN)2 is soluble in excess of KCN.and arrange in the order of true / false.(A) T F T T (B) T T F F (C) F T F T (D) T T T F

4.6 Like CO32–, SO3

2– also gives test with baryta water, Ba(OH)2 .

4.7 Thiourea test is given by NO2– and not by SO3

2–

4.8 Ag2SO3 is insoluble in dilute HNO3 .

4.9 Alkaline sodium stannite gives a black precipitate on reaction with a bismuth salt solution.

4.10 Nitrogen dioxide (NO2) is absorbed by ferrous sulphate solution forming brown solution.

4.11 Heavy metal chlorides like AgCl, HgCl2. etc. do not respond to chromyl chloride test.

4.12 Bright yellow precipitate of silver iodide is partially soluble in concentrated ammonia solution and fairlysoluble in hypo solution.

4.13 Tri-iodide ions (I3–) produced by the reaction of Cu2+ and KI solution are not reduced by of sodiumthiosulphate solution.

4.14 Lead sulphate is soluble in ammonium acetate solution (6M) but barium sulphate is insoluble in dilute HCl.

4.15 HgS dissolves in both sodium sulphide solution and aquaregia.

4.16 Black precipitate of Cu(SCN)2 immediately turns into white precipitate when it reacts with saturated solutionof SO2 in water.

4.17 The group reagent for group basic radicals is NaOH.

4.18 In a solution containing Fe3+ and Mg2+ ions, selective precipitation of Fe(OH)3 is done by aqueous ammoniain presence of NH4Cl.

4.19 Green colour of alkaline tetrahydroxidochromate(III) becomes yellow on adding H2O2.

4.20 Ca2+ ions give yellow precipitate in presence of ammonia with potassium ferrocyanide solution.

4.21 Mg2+ ions in solution gives gelatinous white precipitate of magnesium hydroxide with ammonia solutionand the precipitate is readily soluble in solutions of ammonium salts.

5. FILL IN THE BLANKS5.1 Carbonate gives _________ precipitate (white /yellow/brown) with silver nitrate solution which is soluble in

_______ .

5.2 Soluble bicarbonates give white precipitate with MgCl2 in ________ . (cold/hot)

5.3 Solution of ________ (nitrite / sulphate / bromide) is decomposed by heating with solid urea.

5.4 Ring test is responded by ___________ as well as __________ radicals.

5.5 Bromine develops __________ (brown/blue/red) colouration upon filter paper impregnated with fluorescein.





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5.6 Potassium nitrite solution liberates __________ gas with acidified solution of potassium iodide.

5.7 Sodium bromide gives bromine gas with _________ and hydrogen bromide with _________ .

5.8 I– ions (not in excess) give _________ (red/yellow/green) precipitate with Hg2+ ions.

5.9 The formula of the deep red vapours formed on warming the solid potassium dichromate with KCl in concentratedH2SO4 is ________.

5.10 SO42– ions form ______________ precipitate (white / yellow / brown) with Hg(NO3)2 solution.

5.11 Ag+ ions gives ___________ precipitate (red / brown / yellow / brownish-red) with Na3AsO4.

5.12 Potassium cyanide is used for separating __________ and _________ ions.

5.13 If the ions of group are precipitated by NH4Cl and NH4OH without prior oxidation by concentrated HNO3_________ is not completely precipitated.

5.14 The soluble Prussian blue has chemical composition ___________ .

5.15 Solution of a salt in concentrated HCl is blue, but turns pink on dilution. It indicates the presence of _______radical.

5.16 Manganese ion (Mn2+) gives _____________ coloured borax bead in oxidising flame in cold.

5.17 Ammonium thiocyanate is used in detection of ______________ and ______________ .

5.18 A salt “X” gives crimson red colour in Bunsen flame and also gives brown fumes on reaction with dil. H2SO4.The salt “X” is _____.

IIT-JEE PROBLEMS (PREVIOUS YEARS)

* Marked Questions are having more than one correct option.

1. A white substance (A) reacts with dilute H2SO4 to produce a colourless gas (B) and a colourless solution (C).The reaction between (B) and acidified K2Cr2O7 solution produces a green solution and slightly colouredprecipitate (D). The substance (D) burns in air to produce a gas (E) which reacts with (B) to yield (D) and acolourless liquid. Anhydrous copper sulphate is turned blue on addition of this colourless liquid. Addition ofaqueous NH3 or NaOH to (C) produces first a precipitate, which dissolves in the excess of the respectivereagent to produce a clear solution in each case. Identify (A), (B), (C), (D) and (E). Write the equations ofreactions involved. [JEE 2001, 10/100]

2. An aqueous solution of a substance gives a white precipitate on treatment with dilute hydrochloric acid,which dissolves on heating. When hydrogen sulphide is passed through the hot acidic solution, a blackprecipitate is obtained. The substance is a : [JEE 2002, 3/90](A) Hg2

2+ salt (B) Cu2+ salt (C) Ag+ salt (D) Pb2+ salt

3. When a crystalline compound (X) is heated with K2Cr2O7 and concentrated H2SO4, a deep red gas (A) isevolved. On passing (A) into caustic soda solution, a yellow coloured solution of (B) is obtained. Neutralizingthe solution of (B) with acetic acid and on subsequent addition of lead acetate a yellow precipitate (C) isobtained. When (X) is heated with NaOH solution, a colourless gas is evolved and on passing this gas intoK2Hg4 solution, a reddish brown precipitate (D) is formed. Identify (A), (B), (C), (D) and (X). Write theequations of reactions involved. [JEE 2002, 5/60]





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4. [X] + H2SO4 [Y] a colourless gas with irritating smell; [Y] + K2Cr2O7 + H2SO4 green solution.[X] and [Y] are respectively : [JEE 2003, 3/84](A) SO3

2–, SO2 (B) Cl–, HCl (C) S2–, H2S (D) CO32–, CO2

5. A mixture consists (A) (red solid) and (B) (colourless solid) which gives lilac colour in flame.(a) Mixture gives black precipitate (C) on passing H2S (g).(b) (C) is soluble in aquaregia and on evaporation of aquaregia and adding SnCl2 gives greyish black

precipitate (D).The salt solution with NH4OH gives a brown precipitate.

(i) The sodium extract of the salt with CCl4/FeCl3 gives a violet layer.(ii) The sodium extract gives yellow precipitate with AgNO3 solution which is insoluble in dilute ammonia

solution.Identify (A) and (B), and the precipitates (C) and (D). [JEE 2003, 4/60]

6. A sodium salt on treatment with MgCl2 gives white precipitate only on heating. The anion of the sodium saltis : [JEE - 2004, 3/84](A) HCO3

– (B) CO32– (C) NO3

– (D) SO42–

7. A metal nitrate reacts with KI to give a black precipitate which on addition of excess of KI is converted intoorange colour solution. The cation of the metal nitrate is : [JEE - 2005, 3/84](A) Hg2+ (B) Bi3+ (C) Pb2+ (D) Cu+

8. A white precipitate is obtained when a solution is diluted with H2O and boiled. On addition of excess NH4Cl/NH4OH, the volume of precipitate decreases leaving behind a white gelatinous precipitate. Identify theprecipitate which dissolves in ammonia solution or NH4Cl. [JEE 2006, 3/184](A) Al(OH)3 (B) Zn(OH)2 (C) Mg(OH)2 (D) Ca(OH)2

9. In blue solution of copper sulphate excess of KCN is added then solution becomes colourless due to theformation of : [JEE 2006, 3/184](A) [Cu(CN)4]2– (B) Cu2+ get reduced to form [Cu(CN)4]3–

(C) Cu(CN)2 (D) CuCN

10. MgSO4 + NH4OH + Na2HPO4 white crystalline precipitate. The formula of crystalline precipitate is :

[JEE 2006, 3/184](A) MgCl2. MgSO4 (B) MgSO4 (C) Mg(NH4)PO4 (D) Mg(PO4)2

11. A solution of a metal ion when treated with K gives a red precipitate which dissolves in excess K to give acolourless solution. Moreover, the solution of metal ion on treatment with a solution of cobalt(II) thiocyanategives rise to a deep blue crystalline precipitate. The metal ion is : [JEE - 2007, 3/162](A) Pb2+ (B) Hg2+ (C) Cu2+ (D) Co2+

12. A solution of colourless salt H on boiling with excess NaOH produces a nonflammable gas. The gas evolutionceases after some time. Upon addition of Zn dust to the same solution, the gas evolution restarts. Thecolourless salt(s) H is (are) : [JEE - 2008, 4/163](A) NH4NO3 (B) NH4NO2 (C) NH4Cl (D) (NH4)2SO4





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Paragraph for Question Nos. 13 to 15p-Amino-N, N-dimethylaniline is added to a strongly acidic solution of X. The resulting solution is treated witha few drops of aqueous solution of Y to yield blue coloration due to the formation of methylene blue. Treatmentof the aqueous solution of Y with the reagent potassium hexacyanoferrate(II) leads to the formation of anintense blue precipitate. The precipitate dissolves on excess addition of the reagent. Similarly, treatment ofthe solution of Y with the solution of potassium hexacyanoferrate(III) leads to a brown coloration due to theformation of Z.

13. The compound X is : [JEE 2009, 4/160](A) NaNO3 (B) NaCl (C) Na2SO4 (D) Na2S

14. The compound Y is : [JEE 2009, 4/160](A) MgCl2 (B) FeCl2 (C) FeCl3 (D) ZnCl2

15. The compound Z is : [JEE 2009, 4/160](A) Mg2[Fe(CN)6] (B) Fe[Fe(CN)6] (C) ) Fe4[Fe(CN)6]3 (D) ) K2Zn3[Fe(CN)6]2

Paragraph for Question Nos. 16 to 18When a metal rod M is dipped into an aqueous colourless concentrated solution of compound N, thesolution turns light blue. Addition of aqueous NaCl to the blue solution gives a white precipitate O. Additionof aqueous NH3 dissolves O and gives an intense blue solution.

16. The metal rod M is [JEE 2011, 3/80](A) Fe (B) Cu (C) Ni (D) Co

17. The compound N is [JEE 2011, 3/80](A) AgNO3 (B) Zn(NO3)2 (C) Al(NO3)2 (D) Pb(NO3)2

18. The final solution contains [JEE 2011, 3/80](A) [Pb(NH3)4]2+ and [CoCl4]2– (B) [Al(NH3)4]3+ and [Cu(NH3)4]2+

(C) [Ag(NH3)2]+ and [Cu(NH3)4]2+ (D) [Ag(NH3)2]+ and [Ni(NH3)6]2+

19. Passing H2S gas into a mixture of Mn2+, Ni2+, Cu2+ and Hg2+ ions in an acidified aqueous solution precipi-tates : [JEE 2011, 3/80](A) CuS and HgS (B) MnS and CuS (C) MnS and NiS (D) NiS and HgS

20. Which fo the following hydrogen halides react(s) with AgNO3 (aq) to give a precipitate that dissolves inNa2S2O3 (aq) ? [JEE 2012, 4/136](A) HCl (B) HF (C) HBr (D) HI

21. For the given aqueous reactions, which of the statement(s) is (are) true ? [JEE 2012, 4/136] excess KI + K3[Fe(CN)6] 42SOHdilute brownish -yellow solution

ZnSO4

White precipitate +

Na2S2O3

brownish-yellow filtrate

colourless solution(A) The first reaction is a redox reaction.(B) White precipitate is Zn3[Fe(CN)6]2(C) Addition of filtrate to starch solution gives blue colour.(D) White precipitate is soluble in NaOH solution





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PART - II : AIEEE PROBLEMS (PREVIOUS YEARS)

1. How do we differentiate between Fe3+ and Cr3+ in group IIIrd ? [AIEEE 2002]

(1) By adding excess of NH4OH solution. (2) By increasing NH4+ ion concentration.

(3) By decreasing OH– ion concentration. (4) Both (2) and (3).

2. Which one of the following statement is correct ? [AIEEE 2003]

(1) From a mixed precipitate of AgCl and AgI, ammonia solution dissolves only AgCl.

(2) Ferric ions gave a deep green precipitate on adding potassium ferrocyanide solution.

(3) On boiling a solution having K+, Ca2+ and HCO3– ions we get a precipitate of K2Ca(CO3)2.

(4) Manganese salts give a violet borax bead test in the reducing flame .

3. A red solid is insoluble in water. However it becomes soluble if some K is added to water. Heating the red

solid in a test tube results in liberation of some violet coloured fumes and droplets of a metal appear on the

cooler parts of the test tube. The red solid is : [AIEEE 2003]

(1) (NH4)2 Cr2O7 (2) Hg2 (3) HgO (4) Pb3O4.





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EXERCISE # 1

1.1 (B) 1.2 (A) 1.3 (B) 1.4* (A,B,C) 1.5 (D) 1.6 (C) 1.7* (A,D)1.8 (D) 1.9 (C) 1.10 (A) 1.11 (B) 1.12* (B,C) 2.1 (A) 2.2 (B)2.3 (B) 2.4 (D) 2.5 (B) 2.6 (A) 2.7 (D) 2.8 (C) 2.9 (D)2.10 (A) 2.11 (C) 2.12 (A) 2.13 (B) 2.14 (C) 2.15* (A,B) 3.1 (A)3.2 (D) 4.1 (B) 4.2 (D) 4.3 (D) 5.1 (C) 5.2 (B) 5 . 3 *

(A,B,C,D)5.4 (B) 5.5 (C) 5.6* (A,B,D) 5.7 (C) 6.1 (C) 6.2 (C) 6.3 (D)6.4 (B) 6.5 (D) 6.6 (D) 6.7 (A) 6.8 (A) 6.9 (C) 6.10 (C)6.11 (A) 6.12* (A,C,D) 6.13 (C) 6.14* (A,B,C,D) 7.1 (D) 7.2 (C)7.3 (B) 7.4 (B) 7.5 (B) 7.6 (C) 7.7 (C) 7.8 (D) 7.9 (D)8.1 (B) 8.2 (C) 8.3 (A) 8.4 (D) 8.5 (D) 8.6 (B) 8 . 7 *

(A,B,C,D)8.8* (A,B,C) 9.1 (D) 9.2 (C) 9.3 (C) 9.4 (B) 9.5 (A) 9.6 (D)9.7* (B,C) 9.8 (B)

EXERCISE # 2

PART-I (Objective Type Questions)1. (D) 2. (B) 3. (C) 4. (C) 5. (A) 6. (A) 7. (A)8. (C) 9. (C) 10. (D) 11. (A) 12. (A) 13. (A) 14. (A)15. (D) 16. (A) 17. (B) 18. (C) 19. (D) 20. (A) 21. (B)22. (C) 23. (B) 24. (D) 25. (D) 26. (C) 27. (A) 28. (C)29. (A) 30. (B) 31. (A) 32. (A) 33. (D) 34. (C) 35. (A)36. (D) 37. (D) 38. (C) 39. (A) 40. (A) 41. (A) 42. (D)43. (A) 44. (C) 45. (C) 46. (C) 47. (A,B) 48. (A,B,C,D)49. (A,B,C,D) 50. (A,B,C,D) 51. (A,C,D) 52. (A,C)53. (A,C,D) 54. (A,B) 55. (A,B,C) 56. (C,D) 57. (A,D) 58. (A,D) 59. (B,D)60. (A,C) 61. (B,D) 62. (A,B,C) 63. (A,D) 64. (B,C,D)

PART-II (Subjective Questions)

1. White precipitate of CaCO3 is formed.Ca(HCO3)2 + 2 NH3 (NH4)2CO3 + CaCO3

2. SO32– + Ba2+ BaSO3 (white) ; CO3

2– + Ba2+ BaCO3 (white) ; SO42– + Ba2+ BaSO4 (white)

3. Colour of bromine water is discharged according to the following reaction.BaSO3 + Br2 + H2O BaSO4 (white) + 2HBr

4. NO2– + CH3COOH HNO2 + CH3COO–

3 HNO2 H2O + HNO3 + 2 NONO + Fe2+ + SO4

2– [FeNO]SO4 (Nitroso ferrous sulphate)

5. SO32– + 3 Zn + 8 H+ H2S + 3 Zn2+ + 3 H2O

6. CH3COO(OH)2 Fe (basic ferric acetate)CH3COO¯ + FeCl3 (CH3COO)3 Fe + 3Cl¯ (blood red coloration)

(CH3COO)3 Fe + 2H2O boiled CH3COO(OH)2 Fe (reddish brown) + 2CH3COOH

8. In ammonia solution, potassium cyanide solution and sodium thiosulphate solution forming[Ag(NH3)2]Cl, K[Ag(CN)2] and Na3[Ag(S2O3)2] soluble complexes respectively.





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9. Not in dilute HCl but dissolves in all other reagents.PbSO4 + H2SO4 Pb2+ + 2 HSO4

– ; PbSO4 + 4 CH3COO– [Pb(CH3COO)4]2– + SO42–

PbSO4 + 2 C4H4O62– [Pb(C4H4O6)2]2– + SO4

2–

PbSO4 + 4 OH– [Pb(OH)4]2– + SO42–

10. SO42– + 3 Hg2+ + 2 H2O HgSO4. 2 HgO + 4 H+

Yellow precipitate is owing to the formation of basic Hg(II) sulphate.

11. OHg2NH2I

12. A yellow precipitate of ammonium cobaltinitrite is formed.3 NH4

+ + Na3[Co(NO2)6] (NH4)3 [Co(NO2)6] (yellow) + 3 Na+

13. Hg2Cl2 + 2 NH4OH

black2 )black(Hg)white(ClHgNH + NH4Cl + 2 H2O

Disproportionation reaction.

14. Hg22+ + 2OH– Hg2O (black) + H2O

Hg2O HgO + Hg (grey) ; Disproportionation reaction.

15. Strong acids (nitric acid) and sodium hydroxide.

16. Pb2+ + H2S (atmospheric) PbS (black) + 2H+.

17. PbCl2 is soluble in hot water and it also dissolves in concentrated HCl and KCl solutions forming solublecomplex. ; PbCl2 + 2HCl H2PbCl4 (soluble complex).

18. Yes , forming a soluble complex.HgS + S2– [HgS2]2–

19. It turns yellowish–white owing to the formation of BiO.OH .Bi(OH)3 BiO.OH + H2O

20. With Na2S, along with 2nd group cations, some cations of higher groups i.e., IIIrd and IVth groups may beprecipitated because the higher concentration of S2– ions is obtained according to following reaction.

Na2S 2 Na+ + S2–

To precipitate IInd group cation lower concentration of S2– ions is required (because of low Ksp of IInd groupsulphides) and this can be obtained easily by H2S in presence of dilute HCl.

H2S 2 H+ + S2– ; HCl H+ + Cl–Due to common ion effect the ionisation of H2S is suppressed and the concentration of S2– ions obtained isjust sufficient to precipitate the cations of IInd group.

21. Yes. By the reaction of ammonia according to the following reactions.Cu2+ + 4NH3 [Cu(NH3)4]2+ (deep blue solution).Cd2+ + 4NH3 [Cd(NH3)4]2+ (colourless solution).

22. Bi3+ ; Bi3+ + 3OH– Bi(OH)3 ; 2Bi(OH)3 + 3[Sn(OH)4]2– 2Bi (black) + 3[Sn(OH)6]2–.

23. Salt hydrolyses to Cr(OH)3 .2 Cr3+ + 3 S2– + 6 H2O 2 Cr(OH)3 + H2S

24. Only Fe(II) salts give soluble red iron(II) dimethylglyoxime in ammonical solution.

25. (i) White precipitate, K2Fe[Fe(CN)6] and (ii) Pale blue precipitate.

26. Mn2+ + 2 NH3 + 2 H2O Mn(OH)2 (white) + NH4+ .

In presence of ammonium salts, the reaction proceeds in backward direction.

27. Reddish–violet colouration is obtained owing to the formation of MnO4–.

2 Mn2+ + 5 S2O82– + 8 H2O MnO4

– + 10 SO42– + 16 H+

AgNO3 acts as catalyst.





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28. Zn2+ + 2 NH3 + 2 H2O Zn(OH)2 + 2 NH4+

It is due to the lowering of OH– ion concentration because of common ion effect of NH4+ to such a value that

the Ksp of Zn(OH)2 is not attained.

29. Mg2+ ions will also be precipitated.

30. Sr2+ + NH4+ + SO4

2– SrSO4 (white) + NH4+

Ca2+ + 2 NH4+ + 2 SO4

2– (NH4)2[Ca(SO4)2] (soluble complex).

31. White precipitate is obtained.Ca2+ + 2K+ + [Fe(CN)6]4– K2Ca[Fe(CN)6]

32. 2NO2– + H2SO4 SO4

2– + 2HNO23HNO2 HNO3 + 2NO + O2

2NO + O 2NO2 (Reddish brown)2K + 2NO2 2KNO2 + 2Starch (LVkpZ) + 2 blue

33. Hg2Cl2 + 2NH3 Black

2 )white(Cl)NH(Hg)black(Hg + NH4+ + Cl–.

34. Bi3+ gives BiO+ ion and Sb3+ gives SbO+ ion. Bi3+ + Cl– + H2O BiO.Cl + 2H+.

35. Fe3+ and –, Cu2+ and – , Sn2+ and Fe3+ .2Cu2+ + 4– Cu22 + 22Fe3+ + Sn2+ 2Fe2+ + Sn4+

2Fe3+ + 3– 2Fe2+ + 3 –

36. 3Zn2+ + 2K+ + 2[Fe(CN)6]4– K2 Zn3 [Fe (CN)6]2

37. (i) Mg2++ NH3 + HPO42– Mg(NH4) PO4 (white)

(ii) Zn2+ + 2NH4 OH Zn(OH)2 (white) + 2NH4+

Zn(OH)2 + 4NH4OH [Zn(NH3)4] (OH)2 + 4H2O(iii) Bi3+ + 3– Bi3 (black).

Bi3 + H2O BiO (orange) + 2H+ + 2–.(iv) Na2HPO4 + 12 (NH4)2 MoO4 +23 HNO3 (NH4)3 PMo12 O40 + 2NaNO3 + 21NH4NO3 + 12H2O

(canary yellow)38. (i) 2Cu(BO2)2 (blue) + C 2CuBO2 (colourless) )+ B2O3 + CO

2Cu(BO2)2 + 2C 2Cu (red and opaque) + 2B2O3 + 2CO(ii) AgBr + 2NH3 [Ag(NH3)2] Br(iii) 2Cr(OH)3 + 2Na2CO3 + 3KNO3 fused 2Na2CrO4+ 3KNO2 + 2CO2 + 3H2O(iv) 2Cu(NO3)2 2 CuO + 4NO2+ O2(v) CaSO3 + SO2 + H2O Ca(HSO3)2

39. (i) Na2S + CdCO3 CdS (yellow) + Na2CO3

(ii) CoCl2 + 4NH4 SCN Ether (NH4)2 [Co(SCN)4] (blue colour in etherial solution) + 2NH4Cl

40. A - FeS, CuS, PbS, HgS, CoS, NiS B - H2S C - HNO3D - S E - CuSO4 F - CuSG - [Cu(NH3)4](NO3)2 H - Cu2Fe(CN)6

41. A - FeSO4.7H2O ; B - BaSO4 ; C - SO2 ; D - SO3E - Fe2O3 ; F - FeCl3 ; G - Fe(SCN)3





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42. (A) Pb(NO3)2 (B) PbCl2 (C) PbS (D) Pbl2 or PbCrO4 or PbSO4

43. (A) ZnS ; (B) H2S ; (C) ZnSO4 ; (D) S ; (E) SO2

44. The given unknown mixture contains NH4+, Fe2+ and Cl– ions or NH4Cl and FeCl2

45. A = CdS, B = CdSO4 , C = [Cd(NH3)4] (OH)2 , D = K2[Cd(CN)4], E = BaSO4.46. A = FeCl3 , B = Fe(SCN)3 , C = Fe4[Fe(CN)6]3 , D = CrO2Cl2 , E = PbCrO4 .

47. A = CuCO3 , B = CuO, C = CO2 , D = Cu, E = Cu2[Fe(CN)6], F = Ca(HCO3)248. (A) = CoCl2 , (B) = CoS , (C) = K4[Co(CN)6] , (D) = K3 [Co(CN)6], (E) = Na3 [Co(CO3)3 ]49. A red colouration is obtained. (yky j ax i zkIr gksr k gSA )

50. This gives black cobalt oxide, Co3O4 , upon ignition and this mask the colour of thernad blue (CoAl2O4).

51. (a) Violet (or blackish–purple) precipitate consisting of Zn[Hg(SCN)4] and Cu[Hg(SCN)4] is formed.(b) Zn2+ + [Hg(SCN)4]2– Zn [Hg(SCN)4] (white).

EXERCISE # 31.1 (A - s), (B - r), (C - p), (D - q,t).1.2 (A - p,s ; B - q ; C - r ; D - p)1.3 (A - p,r,t ; B - q,r,s ; C - p,q,r ; D - p,q,r,s)1.4 (A - p, q, r, s) ; (B - p, q , r, s) ; (C - p, q , r, s) ; (D - p, q, r, s)2.1 (A) 2.2 (A) 2.3 (D) 2.4 (C) 2.5 (A) 2.6 (D) 2.7 (A)2.8 (D) 2.9 (D) 2.10 (C) 2.11 (D) 2.12 (D) 2.13 (A) 2.14 (B)3.1 (B) 3.2 (A) 3.3 (B) 3.4 (B) 3.5 (E) 3.6 (D) 3.7 (C)3.8 (A) 3.9 (D) 3.10 (B) 3.11 (A) 3.12 (B) 3.13 (B) 3.14 (B)3.15 (B) 3.16 (B) 3.17 (B) 3.18 (B) 3.19 (A) 3.20 (E) 3.21 (B)4.1 (C) 4.2 (B) 4.3 (B) 4.4 (C) 4.5 (B) 4.6 T 4.7 T4.8 F 4.9 T 4.10 F 4.11 T 4.12 T 4.13 F 4.14 T4.15 T 4.16 T 4.17 F 4.18 T 4.19 T 4.20 F 4.21 T5.1 White ; Nitric acid or ammonia. 5.2 Hot 5.3 Nitrite 5.4 NO2

– , NO3– .

5.5 Red 5.6 Iodine 5.7 Concentrated H2SO4 , H3PO4 .5.8 Red 5.9 CrO2 Cl2 5.10 Yellow 5.11 Brownish–red5.12 Cu2+ and Cd2+ ions 5.13 Fe2+ (ferrous ion) 5.14 KFe[Fe(CN)6].5.15 Cobalt (Co2+). 5.16 Amethyst red 5.17 Co2+ and Fe3+ or Hg2+ ions.5.18 Strontium nitrate

EXERCISE # 4

PART-I

1. Since the white substance 'A' gives a colourless gas ‘B’ with dil. H2SO4 ,such gas may be H2S gas whichfurther produces a green solution and slightly coloured precipitate ‘D’ i.e. sulphur with acidified K2Cr2O7

solution. So substance ‘A’ may contain anion S2–. Since solution ‘C’ produces first a precipitate, whichdissolves in the excess of the NH3 or NaOH the metal cation may be Zn2+.ZnS (A) + H2SO4 ZnSO4 (C) + H2S (B)

K2Cr2O7 + 4H2SO4 + 3H2S K2SO4 + Cr2 (SO4)3 + 3S (D) (yellow) + 7H2O

S + O2 SO2 (E).SO2 + 2H2S 2H2O + 3SCuSO4 + 5H2O CuSO4. 5H2O (blue)

ZnSO4 + 2NaOH Zn (OH)2 (white) + Na2SO4

Zn(OH)2 + 2NaOH Na2ZnO2 + 2H2O





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ZnSO4 + NH4OH Zn(OH)2 (white) + (NH4)2 SO4

ZnSO4 +(NH4)2 SO4 + 2 NH4OH [Zn(NH3)4] SO4 + 4H2ONH4Cl + K2Cr2O7 + H2SO4 (NH4)2SO4 + K2SO4 + CrO2 Cl2 + H2OSo, A = ZnS, B = H2S, C = ZnSO4 , D = S, E = SO2

2. (D)3. 4Cl– + Cr2O7

2– + 6H+ 2CrO2Cl2 (A)(deep red) + 3H2OCrO2Cl2 + 4OH– CrO4

2– (B)(yellow solution) + 2Cl– + 2H2OCrO4

2– + Pb2+ PbCrO4 (C)(yellow)NH4Cl + NaOH NaCl + NH3 + H2O

NH3 + K2Hg4 + H2O (D) + 4K + 3H

So, X = NH4Cl, A = CrO2Cl2 , B = Na2CrO4 , C = PbCrO4 ,

4. (A)5. (A) + (B) lilac colour in flame. So one of the cation may be K+ .

(a) (A) + (B) )g(SH2 (C) black precipitate.

(b) (C) regiaaquainlelubso soluble nEvaporatio Residue 2SnCl Greyish black precipitate (D).

(A) + (B) OHNH4 brown precipitate. So second cation may be Hg2+.(i) Sodium carbonate extract of salt 34 FeCl/CCl violet colour..

(ii) Sodium extract of salt 3AgNO yellow precipitate 3NH soluble.

So the anion may be I– .

(a) HgI2 + H2S HgS (C) (black) + 2HI.(b) 3HgS + 6HCl + 2HNO3 3HgCl2 + 2NO + 4H2O + S.

HgCl2 + SnCl2 Hg (D) (greyish black) + SnCl4.2KI (B) + HgI2 (A) K2[HgI4] (orange).2K2[HgI4] + NH3 + 3KOH [HgOHg(NH2)I] ( brown).Sodium carbonate extract of salt contains NaI.2NaI + 2Fe3+ 4CCl I2 (violet)+ 2Na+ + 2Fe2+.I2 dissolves in CCl4 giving violet colour solution.AgNO3 + NaI AgI (yellow) + NaNO3.AgI is insoluble in ammonia solution.

So, (A), (B), (C) and (D) are HgI2, KI, HgS and Hg respectively.

6. (A) 7. (B) 8. (B) 9. (B) 10. (C) 11. (B) 12. (B)

13. (D) 14. (C) 15. (B) 16. (B) 17. (A) 18. (C) 19. (A)

20. (A,C,D) 21. (A), (C) & (D)

PART-II

1. (D) 2. (A) 3. (B)

contents qualitative analysis syllabus ... in our scheme fe2+ is not there even if it is present,...

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