Flame test
The substance is moistened with conc. HCl, and the mixture, on a platinum wire is
shown in the edge of the non-luminous Bunsen flame.
Flame Colour
Inference
Golden yellow
Na
Lilac (violet)
K
Brick – red
Ca
Crimson
Sr
Apple green
Ba
Bluish green
Cu
Green
Borates
Livid blue
Pb, Sb, Bi
Dil. Acid group
To about 5 mg of the substance add about 0.5 ml of dil. HCl. Observe the
reaction in the cold and then heat it on a water bath.
Observation
1. Brisk effervesce, the gas turns lime/Baryta water milky
Inference
Carbonate is
Present.
2. Colourless gas (SO2) with the smell of burning sulphur .The gas turns Sulphite is
Present.
a filter paper dipped in acidified potassium dichromate green.
3. Colourless gas with the odour of rotten eggs (H2S) is evolved. The gas Sulphide is
turns lead acetate paper black and
Present.
cadmium acetate paper yellow.
4. Vineger smell. Red coloration/ppt with neutral ferric chloride.
Acetate is
5. Mix 20 mg of the substance with 1ml of ethyl alcohol and 5 drops of con.
Present.
H2SO4, Heat in a hot water rack for 10 minutes, and pour into 2 ml of Na2CO3
solution.  Fruity odour
Addition of Conc. H 2SO4 + MnO2, heat
Observation
Inference
1. Greenish yellow pungent smelling gas (HCl) which fumes in Chloride is
moist air. Dense white fumes (NH4Cl) with a drop of ammonia Present.
on a glass rod
2. Reddish brown fumes (Br2) are evolved.
3. violet vapours (I2) are evolved.
4.On warming, brown gas (NO2)With characteristic smell is
evolved. The brown colour is deepened by the addition of
copper turnings.
Bromide is
Present.
Iodide is
Present.
Nitrate is
Present.
Silver nitrate group
Add silver nitrate to Neutralized sodium carbonate extract
1
2
3
A curdy white precipitate
(AgCl), insoluble in dil.HNO3,
but soluble in ammonia solution.
A pale yellow precipitate (AgBr),
insoluble in dil. HNO3,
but sparingly soluble in
ammonia solution.
A yellow precipitate, insoluble
in both dil. HNO3 and ammonium
solution.
Chloride is
confirmed.
Bromide is
confirmed.
Iodide is
confirmed.
Test for Bromide and Iodide:
To the substance in dil. HNO3 add drops of KMnO4 solution until
the pink colour persists. Add CCl4 and shake.
Reddish brown colouration
of CCl4 layer
Bromide is
confirmed.
Violet colouration of CCl4
layer.
Iodide is
confirmed.
Nitrate : Brown ring test
The sodium carbonate extract is acidified with dil. H2SO4.
An equal volume of freshly prepared FeSO4 solution is added.
Holding the test-tube in an inclined position con. H2SO4 drops are added
without shaking.
A brown ring is formed at
the junction of the two
layers
Nitrate is
confirmed.
Sulphate : BaCl2 test
To the sodium carbonate extract add dil. HCl till no more
CO2 is evolved. Add 1-2 ml of dil. HCl and BaCl2 solution.
A white precipitate insoluble in dil. HCl is formed Sulphate is Confirmed
Borate: Flame Test
The substance is mixed with calcium flouride and con.
H2SO4 to get a paste. Hold some of the paste on a platinum
loop, just outside the base of the Bunsen flame.
A green flame is formed
Borate is confirmed.
Phosphate : Amm. Molybdate test
To the sodium carbonate extract add dil. HNO 3ill no
more CO2 is evolved. Add 1-2 ml of amm. Molybdate.
Warm.
Yellow ppt
Phosphate is confirmed.
Oxalate
Acidify the sodium carbonate extract with dilute acetic
acid and add calcium chloride solution. White ppt.
Divide the precipitate into two parts –
•Add dilute HCl  ppt dissolves
•Add hot dil. H2 SO4 and potassium permanganate drop
wise  it gets decolourised
Oxalate is confirmed
Analysis of Cations
•Preparation of the original solution
A small quantity of the substance (15 mg) is treated with the following
solvents in the given order.
•Distilled water
•dil.HCl,
•dil.HNO3
•con.HCl
•aqua regia (3 vol. con. HCl + 1 vol. con. HNO3).
Observe the solubility in the cold, then heat to boiling. If any gases are
formed, boil them off. Dissolve 50 to 100 mg of the substance in the
suitable solvent and prepare the solution. This solution is often referred
to as the original solution.
Cations/ Groups / Group reagents
Group
Group
reagent
Cations
Ppt formed
I
Dil. HCl
Pb2+ , Ag
Hg1+
,
Chlorides
II
Dil. HCl + H
S
Pb2+ , Bi3+ ,
Cd2+ , Cu2+ ,
Sn2+ , As3+ ,
Sb3+
Sulphides
III
NH Cl + NH
OH
Fe3+ , Al3+ ,
Cr3+
Hydroxides
IV
NH Cl + NH
OH + H S
Co2+ , Ni2+ ,
Zn2+ , Mn2+
Sulphides
V
NH Cl + NH
OH
+ NH CO
Ca2+ , Ba2+ ,
Sr2+
Carbonates
VI
No group
reagent
Mg2+ , NH+ ,
K+
--
1+
Separation of Cations into Groups
To 1 ml of the original solution in a centrifuge tube, dil. HCl is added until
precipitation, if any, is complete Centrifuge.
Residue
-1
White,
may
contain
PbCl2,
Hg2Cl2
or
AgCl.
Centrifugate-1 Heat on a water bath; pass H2S gas until the
precipitation is complete. Centrifuge.
Residue-2
Centrifugate-2 : (Eliminate the interfering anions if
May
necessary.Boil off H2S Add 3 drops of con.HNO3 and
Contain
boil.Add 100 mg solid ammonium chloride, heat on a
Black:HgS, PbS, water bath. Add ammonia solution till alkaline, and
CuS.
add 2 drops excess. Warm. Stir. Centrifuge.
Brown:Bi2S3.
Residue-3:
Centrifugate-3: Add 2 drops
Yellow:CdS,
May contain
of NH3 solution. Warm. Pass
Reddish-brown:Fe(OH)3 H2S to complete
Group- Sb2S3,SnS2
Green:Cr(OH)3
precipitation. Centrifuge.
Group – 2
1
White:Al(OH)3
Wash the residue
present present
Group 3
Present
Separation of Cations into Groups
Contd….
Residue-4:
May contain
Black:
CoS, NiS
Pink: MnS,
White:
ZnS
Group 4
present
Centrifugate-4: Place in a china dish. Acidify with dil. Acetic
acid. Evaporate to a pasty mass. Add 5 drops of
con.HNO3.Heat to dryness (till fumes stop)7 Dissolve the
residue in 5 drops of dil. HCl and 1 ml water. Add (in testtube) 5 drops of 20% NH4Cl. Add NH4OH with shaking till
alkaline. Add excess of 10% (NH4)2CO3 soln. Warm at
5060oC. Centrifuge. Wash.
Residue -5
May contain
White:
BaCO3,SrCO3,
CaCO3
Group 5 present
Centrifugate-5:
Evaporate to a pasty mass, add 0.5 ml
con.HNO3.
Heat to dryness
White residueGroup-6 present
Analysis of Group I
Separation of group 1 cations: The Residue-1 is washed with cold water containing a few
drops of dil. HCl, and centrifuged. To the residue, add 1 ml of hot water. Heat to boiling for 12 minutes. Centrifuge while hot. Transfer the centrifugate quickly to another test tube.
Residue (Residue 1.1): White: May contain Hg2Cl2
Centrifugate (1.1) : May contain PbCl2.
and AgCl. Wash with boiling water to remove the
Divide into 3 parts.
undissolved PbCl2.Treat the residue with 0.5 ml
1. Cool under tap – White ppt.
warm dilute NH3 solution. Stir. Centrifuge.
reappears . – Pb2+ is confirmed.
Residue (1.2), Black:Hg + Centrifugate (1.2): May
Hg (NH2) Cl. Hg22+
contain Ag (NH3)2Cl. Divide 2. Add 2 drops of potassium chromate
– Yellow ppt. (PbCrO4).- Pb2+ is
present. Dissolve the
into 2 parts.
confirmed.
ppt. in aqua-regia, heat,
1. Add dil.HNO3. White
divide into two parts.
3. Add 2 drops of KI solution –Yellow
ppt. (AgCl) – Ag2+ is
ppt. (PbI2).Boil the ppt. with water and
1. Add stannous chloride confirmed.
a few drops of acetic acid and cool.
- White grayish ppt.
2. Add KI solution- Yellow
2+
The ppt. dissolves on heating and
Hg2 is confirmed.
2+
ppt. (AgI) –Ag is
reappears as golden spangles on
2. Add drops of KI
confirmed.
cooling – Pb2+ is confirmed.
solution- Red or Yellow
ppt. Hg22+ is confirmed.
Analysis of Group II A
Residue-2A: May contain Hg2+, Pb2, - Bi 3+ , Cu2+ and Cd2+ Add 1.5 ml dil.HNO3. Warm and centrifuge.
Residue
Centrifugate-: May contain nitrates of Pb, Bi, Cu, and Cd. Add excess con.NH3
solution and centrifuge.
Black: HgS,
Residue May contain Bi3+ and Pb2+. Add 1ml
Centrifugate: May contain Cu2+,
NaOH solution. Warm. Centrifuge.
and Cd2+.
Wash with
Residue May be Bi (OH)3 wash Centrifugate
1. a) solution is colourless - Cu2+
Water. Dissolve in 3 drops
with water. Divide the
May contain Pb is absent.
con. HCl and 1 drop con.
precipitate into 2 parts.
(OH)4-. Acidify with
HNO3. Heat. Divide into 2
b) Pass H2S gas through the
1. Add sodium stannite
dil. Acetic acid.
parts.
solution. Yellow precipitate – Cd2+
reagent. Immediate
Divide into 2 parts.
is confirmed.
1. Add 2 drops
blackening of precipitate. –
1. Add K2CrO4
SnCl2.White grey
3+ is present.
Bi
2. a) Solution is blue – Cu2+ is
2+
solution Yellow
precipitate. Hg is
present. Divide into 2 parts
2. Dissolve in 3 drops of
precipitate. Pb2+ is
confirmed
Conc.HNO3. Pour 1 drop of
confirmed.
1. Add acetic acid in excess and 1
2. Add KI solution Red
the solution in 5 ml waterdrop [K4 Fe (CN)6 ] solution. Red2.
Add
dil.H
SO
–
precipitate. dissolving in
2
4
white turbidity- Bi 3+ is
brown precipitate. Cu2+ is
2+
white precipitate.
excess KI. Hg is
confirmed.
confirmed.
Pb2+ is confirmed.
confirmed.
3. Dilute the above solution.
2. Add KCN (poison) to discharge
To one drop, on a spot plate,
blue colour. Pass H2S. Yellow
add a drop of Cinchonine – KI
precipitate. Cd2+ is confirmed.
reagent. Orange-red spot- Bi3+
is confirmed.
Analysis of Group II B
The centrifugate-2Amay contain Sb3+ and Sn2+ . Centrifuge. Wash the Residue. Reject
washings. Treat the residue with 1ml conc. HCl. Warm on water bath for 3 minutes. Stir.
Centrifuge.
ResidueMay contain
HgS. Black:
It is tested
for Hg as
given in the
Group 2 A.
(Yellow
precipitate.
of As2O3 also
appears here.
Centrifugate- May contain HSbCl4 and H2SnCl6.Take
small portions and test as under:
1. Add NH3 solution till just alkaline. Add 0.3 gms of
oxalic acid. Pass H2S for 30 seconds. – Orange
precipitate. (Sb2S3)-Sb 3+ is present.
2. To 2 drops of the solution on a spot plate, add a
minute crystal of NaNO2 Stir. Add 2 drops of
Rhodamine-B reagent. Violet colouration- Sb 3+ is
present.
3. Treat 0.3ml of the solution with 10mg of Mg powder.
Add 2 drops of FeCl3 solution, 3 drops of 5% tartaric acid
solution, 2 drops of dimethyl glyoxime reagent, then
dil.NH3 solution until basic. Red colouration. Sn4+ is
present.
ANALYSIS OF GROUP III
The group III precipitate. (Residue-3) may contain Fe3, Al3+ and Cr3+.
Dissolve the precipitate in 2ml of NaOH solution in a boiling tube, add
1ml of 3% H2O2. Boil gently and centrifuge.
Residue: May Contain Fe3
.Dissolve the precipitate in 0.5ml of
dil.HNO3. Add potassium ferrocyanide –
Deep blue precipitate.-Fe3+ is present
Confirmatory test for Fe2+And Fe3+
1. To the original solution add
Centrifugate: May contain NaAlO2 (colourless), and NaCrO4
(yellow).(Test only for Al if the solution is colourless. Test
portions as under.
1. Add dil. HCl till acidic. Add NH3 solution. till just alkaline,
add 1 drop more. Warm. White Gelatinous precipitate of
Al(OH)3. .Al3+ is present.
2. Centrifuge the above precipitate. Dissolve in dil. HCl, add
ammonium thiocyanate solution.
0.3ml ammonium acetate solution and1 drop of aluminon
a)No colouration.Fe2+ is confirmed
.
3+
b)Deep red colouration. Fe3+ is confirmed. reagent A bright red precipitate. Al is confirmed.
3. To a drop of the centrifuge-3.1solution on a spot plate, add
2. To the original solution Potassium
1drop of 1% aqueous alizarin-S. Add drops of acetic acid until
ferrocyanide solution is added.
violet colour appears. Add a few more drops of acetic acid. A
a)Deep blue colour. Fe3+ is confirmed.
red precipitate or colouration appears. Al3+ is confirmed.
b)Pale blue colour. Fe2+ is confirmed.
4.Acidify with dil. acetic acid. Add 1 drop of lead acetate
solution. Yellow precipitate.(PbCrO4).Cr3+ present.
5. Acidify with dil. HNO3, cool, add 0.5ml of amyl alcohol or
ether and 2 drops of 3% H2O2.Shake. Allow to stand. The
organic layer becomes blue which is
unstable. Cr3+ is confirmed.
ANALYSIS OF GROUP IV
The group IV precipitate (Residue-4) may contain Co2+, Ni2+, Mn
absent.
Stir the precipitate in the cold, with very dil. HCl. Centrifuge.
2+
and Zn2. If not black, Co2+ and Ni2+ are
Residue: May Contain Co2+and Ni2+. Centrifugate: May contain Mn2+ and Zn2+. Boil off to expel H2S Cool. Add excess
Dissolve the precipitate. in 5 drops of of NaOH solution until basic and 4 drops of 3% H2O2 solution. Warm for 3
aquaregia. Divide into 3 parts.
minutes. Centrifuge.
1. Add amyl alcohol and 50mg solid Residue-4.2: May contain Mn 2+. Centrifugate-4.2: May contain Zn2. Divide into 3
NH4SCN. Shake. Blue colouration in Dissolve in 1ml dil.HNO3. Divide parts.
the alcohol layer – Co2+ is confirmed. into 2 parts.
1. Pass H2S. White precipitate. (ZnS). Zn2+ is
2. Add drops of 1% alcoholic alpha- 1. Add 2 drops of 3% H2O2.
confirmed.
nitroso-betanaphthol. Reddish
Warm to decompose excess
2. Just acidify with dil. H2SO4, add 5 drops of
brownprecipitate. Co2+ is confirmed. H2O2. Cool. Add 50 mg NaBiO3. 0.1% CuSO4 solution and 5 drops of ammonium
Shake. Allow to stand. The
mercury thiocyanate reagent. Stir. Violet
3. Add 1 drop of NH4Cl solution.
Make it faintly alkaline with NH3
solution turns purple – Mn 2+is precipitate. Zn2+ is confirmed.
solution. Add 3-5 drops of dimethyl confirmed.
3. Just acidify with dil.H2SO4. Add a drop of dil.
glyoxime reagent. Redprecipitate.
2. Take the other part in a boiling cobalt nitrate solution, 0.5ml of ammonium
2+
Ni is confirmed.
tube with 0.5 ml H2O. Add 2
mercury-thiocyanate reagent. Stir. Pale blue
drops of 3% H2O2. Boil to
precipitate.
decompose excess H2O2. Cool. Zn2+ is confirmed.
Add 0.5ml con.HNO3 and 250mg
PbO2. Boil. Allow to stand – A
purple solution is formed. Mn2+
is confirmed.
ANALYSIS OF GROUP V
The group V precipitate. (Residue-5) may contain Ba2+, Ca2+ and Sr 2+. Dissolve the precipitate in 1
ml of dil. acetic acid . Warm. Divide into three parts and test as follows.
Part 1
Add a few drops
of K2Cr2O7 
Yellow ppt of
BaCrO4. Ba2+ is
confirmed.
Dissolve the
residue in a few
drops of conc.
HCl, Apply
flame test.
Yellowish green
flame. Ba2+ is
confirmed.
Part 2
To 1ml of the solution add1ml of
saturated ammonium sulphate
solution followed by 0.1 g
sodium thiosulphate. Heat on
water bath for 5 minutes. White
ppt. of SrSO4, Sr2+ is present.
Add a few drops of conc. HCl to
the ppt, apply flame test.
Crimson flame. Sr2+ is confirmed.
Part 3
Divide into two parts 1. Add NH3 solution to get the
smell of ammonia. Add
ammonium oxalate solution.
Warm. White precipitate. Ca2+ is
confirmed.
2. The other portion is
evaporated to a pasty mass. Add
1 drop of conc. HCl. Apply flame
test. Brick-red flame. Ca2+ is
confirmed.
ANALYSIS OF GROUP VI
The centrifugate from Group VI is evaporated to dryness. A white residue is
obtained. Group VI cations are present.
Dissolve in a few drops of dil. HCl. Add 1ml of water. Divide into 3 parts.
1. Add 3 drops NH4Cl, and NH4OH till alkaline. Add 4 drops of
Na2HPO4. White precipitate. Mg2+ confirmed.
2. Add 2 drops of Magneson reagent and NaOH solution drops till
alkaline.
A blue precipitate. Mg2+ is confirmed.
3. Add a few drops of 2% oxine solution ( 8 – hydroxyquinoline).
Warm. Pale yellow precipitate of Mg oxinate. Mg 2+ Present.