Element Analysis

8/3/2019 Element Analysis

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Certificate

This is to certify that the project entitled Dyes has been

submitted by Soumya Subhra Dutta a student of class

XII-A under the Roll no.__________ for the academic

session 2009-2010. He has completed the project work

Chemistry Department under direct supervision of the

undersigned as per the requirement for the Board

Examination.

(----------)

Department of Chemistry

----------------------


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ACKNOWLEDGEMENT

We want to express our sincere gratitude to our

Chemistry teacher Miss Rimpa Mukherjee for her

guidance, encouragement and kind co-operation without

which my chemistry project wont have been possible.

We are also grateful to Mr. Manojeet Das ,

LABORATORY ASSISTANT, CHEMISTRY

DEPARTMENT for his valuable help during the

preparation of this project.

SOUMYA SUBHRA DUTTA

XII-A

Roll No.________________


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GENERAL INTRODUCTION

Qualitative Analysis: The type of analysis that deals with themethods which are used to determine the constituents of acompound.

Radical: A radical is defined as an atom or group of atoms whichcarries charge and behaves as a single unit in chemical reactions.

Radicals carrying positive charge are called Basic Radicals andradicals carrying negative charge are called Acidic radicals.

Sublimation: It is a process by which a salt directly changes into agaseous phase without melting when heated. On cooling, vapourscondense back to the solid state.

Importance of Preliminary test in qualitative analysis

Preliminary tests give authentic information about an ion in the salt.For example, golden yellow color in flame test shows the presence ofsodium. In a charcoal cavity test, brown residue shows the presenceof cadmium in a salt and so on.


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Groups reagents for different groups

Group I Dilute HCl

Group II H2S in the presence of dil. HCl

Group III NH4OH in presence of NH 4Cl

Group IV H2S in presence of NH 4OH

Group V (NH4)2CO3 in presence of NH 4Cl and

NH4OH

Group VI NO specific reagent.


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List of Acid Radicals List of Basic Radicals

Cl- SO 42- NH4+ Mn2+

Br- PO43- Pb2+ Zn2+

I - CO32- Cu2+ Ba2+

NO3- SO 32- As3+ Sr 2+

CH3COO- S2- Fe3+ Ca2+

C2O42- NO2- Co2+ Mg2+

Ni2+


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PART I

Test Observations Inference

Dil. H 2S0 4 test : To a

small quantity of salt ,

1 -2 ml of dil. H 2SO4 is

added.

1) Colorless, odorless gas

with brisk effervense

turns water milky.

2) Colorless gas, pungent

smell, turns acidified

K2Cr2O7 paper green.

3) Colourless gas with

rotten egg smell, turns

lead acetate paper black.

4) Reddish brown gas,

pungent smell, turns

FeSO 4 black.

Gas Radical

CO2 CO32-

SO 2 SO 32-

H2S S 2-

NO2 NO2-

Chemicals Reactions involved in dil. H 2SO 4 test:

1) Carbonate: CaCO 3 + H2SO 4 CaSO4 + H2O + CO2

2) Sulphides: ZnS + H 2SO 4 ZnSO 4 + H2S


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3) Sulphites: Na 2SO 3 + H2SO 4 Na2SO 4 + SO2 + H2O

4) Nitrites: 3KNO 2 + 3H2SO 4 3KHSO4 + HNO3 + H2O + 2NO

2NO 2 + O2 2NO 2 (brown fumes)

PART II


To a small quantity of slat

2-3 ml of concentrated

sulphuric acid is added.

1)Colorless gas with

pungent smell, white fume

with aqueous ammonia

NH4OH white ppt. AgNO 3

2) Reddish brown vapors

with pungent smell, turns

starch paper yellow. It

doesnt turn FeSO 4 soln

black.

3) Deep violet vapors with

Gas Radicals

HCl Cl-

Br2 Br-

I 2 I -


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Group Zero

Detection of NH 4+

Test Observation Inference

Nessler reagent test:

To the salt soltn few

drops of Nessler reagent

were added.

Brown ppt. formed (The

brown color is due to the

formation of

Mercuric Amido Iodide

[NH2.HgO.HgI] ).

NH4+ is present.

Chemical reactions involved in it are:

Nessler Reagent test:

2K2[HgI 4] + NH3 + 3KOH NH2.HgO.HgI + 7KI +

2H2O


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Group 1

Detection of Pb 2+ ion


1) HCl test: To the salt

soln , dil. HCl is added to

the solution.

2) K2CrO4 test: To the

salt solution Potassium

chromate, K 2CrO4 is

added.

3) KI test: To the salt

soln Potassium Iodide is

added.

White ppt. of is formed

which is soluble in water.

Yellow ppt. is formed due

to formation of PbCrO 4.

Yellow ppt. is formed due

to the formation of PbI 2

which is soluble in hot

water reappears as

Golden spangles on

cooling.

Pb2+ is present.

Pb2+ is present.

Pb2+ is present.

Chemical reactions involved in it:


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HCL test: Pb (NO 3)2 + 2 HCl PbCl2 + 2HNO3

K2CrO4 test: PbCl 2 + K2CrO4 PbCrO4 + 2KCl

KI test: PbCl 2 + KI PbI 2 + 2KCl.

Detection of Cu2+


Potassium Ferro cyanide

test: To the sample, few

drops of K 4[Fe(CN)6] is

added .

Chocolate Brown ppt. of

Cuprous Ferro cyanide

Cu[Fe(CN)6] is obtained.

Cu2+ is present


Potassium Ferro cyanide test: 2CuSO 4 + [Fe (CN)6] + 2 K2SO 4.


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Group II A

Detection of As 3+


1) Ammonium molybdate

test: To a part of the

soln, add ammonium

molybdate and heat it.

2) Magnesia mixture

test: The second part of

the soln is made alkaline

with NH 4OH solution and

magnesia mixture is

added.

3) H2S gas test: The

salt soln is added with dil

H2S gas.

A yellow ppt. is formed.

A white ppt. is formed.

Yellow ppt. is formed.

As3+ is present.

As3+ is present.

As3+ is present.


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Group II B

Detection of Fe 3+

Test Inference Observation

Potassium Ferro

cyanide test: To the

sample, few drops of

K4[Fe(CN)6] is added .

Deep Blue coloration of

ferric ferro cyanide is

formed.

Fe3+ is present.


4FeCl3 + 3K4[Fe(CN)6] 12KCl + Fe[Fe(CN)6]3.


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Group III

Detection of Al 3+


1) Lake Reaction: A

white ppt. Al(OH) 3 is

dissolved in dil HCl and

drop wise NH 4OH is

added till the blue color

develops.

2) Cobalt Nitrate test:

The salt is acted with

cobalt nitrate.

A blue lake is seen

Blue mass is produced.

Al3+ is present

Al3+ is present

Chemical Reactions involved in it are:

Lake test: AlCl 3 + 3NH4OH NH4Cl + Al(OH)3


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Group IV

Detection of Ni 2+


DMG test: To a small

amount of salt solution,

few drops of NH 4OH is

added along with a few

drops DMG(Dimethyl

Glyoxime)

Rose red coloration or

ppt. is formed.

Ni2+ is present and

confirmed.


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Detection of Zn2+


1) Sodium Hydroxide

test: To the salt soln,

few drops of NaOH are

added.

2) H2S gas test: To the

salt soln, few drops of

NH4OH soln. are added

and then H 2S gas is

passed.

3) Potassium Ferro

cyanide test: To the

sample, few drops of

K4[Fe(CN)6] is added .

White ppt is formed that

is dissolved in excess

NaOH.

White ppt is formed

White ppt is formed of

Zinc Ferro cyanide.

Zn2+ is present

Zn2+ is present

Zn2+ is present

Chemical reaction involved in it is:

NaOH test: ZnCl 2 + NaOH ZnOH +NaCl


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K4[Fe(CN)6] test: ZnCl 2 + K4[Fe(CN)6] Zn[Fe(CN)6]

Detection of Co 2+


Ammonium thio cyanate

ether test: To the salt

soln, crystals of NH 4SCN

are added and 1 ml of

amyl alcohol.

Blue coloration of organic

layer.

Co2+ is present.

Chemical Reactions involved in it are:

Ammonium thiocynate ether test:

CoCl2 + NH4SCN (NH4)2[Co(SCN)4] + 2 NH4Cl.


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Detection of Mn2+


1) Sodium Hydroxide

and Bromine test: To

the salt soln, NaOH soln

is added and well shaken

and then Br 2 water is

added.

2) Lead Peroxide test:

To a black ppt. conc.

HNO3 and lead peroxide

are added. It is boiled,

cooled and allowed tosettle down.

A white ppt. was formed.

But after addition of Br 2

water it turned black or

brown.

Pink colored soln is

observed.

Mn2+ is present

Mn2+ is present.


1) NaOH and Br 2 water test: MnCl 2 + 2NaOH Mn(OH)2 + 2NaCl


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Mn(OH)2 + Br2 + H20 MnO(OH)2

2) PbO 2 test: MnS + PbO 2 + HNO3 2HMnO4 + Pb(NO)3 + 2 H20.

Group V

Detection of Sr 2+


1) Ammonium Sulphate

test: To the salt soln, 1

ml of ammonium sulphate

soln is added and

warmed.

2)Flame test: Perform

flame test with original

salt


Crimson red flame visible

through blue glass.

Sr 2+ is present

Sr 2+ is present.

Chemical reactions involved in it are


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1) Ammonium Sulphate test: SrCO 3 + 2 CH3COOH (CH3COO)2Sr +

CO2 + H20

(CH3COO)2Sr + (NH 4)SO 4 2CH3COONH4 + SrSO 4

Detection for Ba 2+


1) (NH4)2CO3 test: To a

small quantity of salt

soln, few drops of

NH4OH and (NH 4)2CO3 is

added.

2) K2CrO4 test: To the

salt solution Potassium

chromate, K 2CrO4 is

added.

3) (NH4)2SO 4 test: To a

small of salt soln,

(NH4)2SO4 is added.

A white ppt. soluble in

acetic acid is formed.



Ba2+ is present

Ba2+ is present

Ba2+ is present.



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BaC03 + 2CH3COOH (CH3C00)2Ba + CO2 + H2O

1) K2CrO4 test: (CH 3C00)2Ba + K2CrO4 2CH3COOK + Ba2CrO4 + H20.

Detection of Ca 2+


1)Ammonium Oxalate

test: To the salt soln.

add 1-2 ml of ammonium

oxalate and a little

ammonium hydroxide is

added to it.

2) Flame test: Perform

Flame test with the

original salt.

White ppt. is formed.

Brick red flame yellow

through blue glass.

Ca2+ is formed.

Ca2+ is formed.


CaCO3 + 2CH3COOH (CH3COO)2Ca + CO2 + H2O


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1) Ammonium Oxalate test:

(CH3COO)2Ca + NH4C2O4 2CH3COONH4 + CaC2O4

Group VI

Detection of Mg 2+


1) Ammonium Phosphate

test: To the salt soln,

some solid NH 4Cl and

NH4OH is added. Then

ammonium phosphate

soln. added.

2)Charcoal cavity test:

Perform charcoal cavity

cobalt nitrate test with


A pink mass is obtained.

Mg2+ is present.

Mg2+ is present.


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the salt soln.


1) Ammonium phosphate test: MgCl 2 + NH4OH + (NH4)2HPO4

Mg(NH4)PO4 + 2NH4Cl + H20

Detection of Na +


1) Potassium pyro-

antimonate test: To the

salt soln, potassium pyro

antimonite soln is

added.


flame test the salt soln.

A white milkiness is

observed.

Persistent golden yellow

flame invisible through

blue glass.

Na+ is present

Na+

is present.


Potassium pyro-antimonate test: 2NaCl + K 2H2Sb 207 2KCl +


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Na2H2Sb 207

Detection of K +


1) Sodium Cobalt nitrile

test: To the salt soln

NaOH soln is added and

then freshly prepared

sodium cobalt nitrite

soln is added.

2) Picric acid test: To

the salt soln, picric acid

is added.



Yellow shining crystalline

ppt. is formed.

A pale violet flame is

K+ is present.

K+ is present.

K+ is present.


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flame test with the salt

soln.

observed and it is pink

through the blue glass.


1) Sodium cobalt nitrite soln:

3KCl + Na3[Co(NO2)6] 3NaCl + K3[Co(NO2)6]

2) Picric acid test:KCl + C 6H2(NO2)3OH HCl + C6H2(NO2)3OK.

Element Analysis

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