QUALITATIVE AND QUANTITATIVEANALYSIS
The difference between qualitative and quantitative
analysis in chemistry is that the qualitative analysis in
chemistry gives the presence or absence of different
chemical components in a sample
whereas quantitative analysis in chemistry gives the
amount of different chemical components present in
a given sample.
Qualitative data analysis is based on classification of
objects (participants) according to properties and
attributes whereas quantitative analysis is based on
classification of data based on computable
values. Qualitative analysis is subjective
whereas quantitative is objective.
3.
ACID AND BASICRADICALS
The ion formed after removal of
Hydrogen ion (H io
⁺ n) from an acid is
called acid radical. Ex: when HCl loses
H ion
⁺ s, it forms Cl which is an acid
⁻
radical.
The ion formed after removal of
hydroxide ions (OH ions
⁻ ) from a
base is called basic radical. Ex: when
NaOH loses OH ions
⁻ , and forms Na⁺
ions ,which is an basic radical.
5.
Experiment Observation Inference
Color:Note down the
color of the given salt.
Blue or Bluish green May be Cu2+
or Ni2+
Greenish May be Ni2+
Light Green May be Fe2+
Dark brown May be Fe3+
Pink May be Co2+
Light pink, flesh color or
earthy color
May be Mn2+
White
May be Cu2+
, Ni2+
, Fe2+
, Fe3+
and
Co2+
etc are absent.
Smell: Take a pinch of the salt
between your fingers and rub with
a drop of water.
Ammonical smell
May be NH4+
Density Heavy May be the salt of Pb2+
or Ba2+
Deliquescence
Salt absorbs moisture and
becomes paste like.
If colored, may be Cu(NO3)2 or
FeCl3.
If colorless, May be Zn(NO3)2,
chlorides of Zn2+
, Mg2+
etc.
6.
EXPERIMENT OBSERVATION
INFERENCE
First makea small cavity on a
charcoal box using a borer.
Mix a small quantity of the
salt with double its quantity
of sodium carbonate in a
watch glass. Place the
mixture in the cavity made
on the block of charcoal.
Moisten the mixture with
a drop of water. Direct
the reducing flame of the
Bunsen burner on
the cavity by means of
a mouth blowpipe.
Heat strongly for
sometime and record
the observations.
RESIDUE
METALLIC
BEAD
Hot Cold
Yellow White None Zn2+
Brown Yellow
Grey bead
which marks
the paper
Pb2+
None None
Red beads or
scales
Cu2+
White
residue
which
glows
None None Ba2+
, Ca2+
, Mg2+
Black None None
Nothing definite
- generally
coloured salt
CHARCOAL CAVITY TEST
7.
EXPERIMENT
OBSERVATION
(COLOUR OF THE
RESIDUE)
INFERENCE
Putone or two drops of
cobalt nitrate solution on the
white residue left after
charcoal cavity test. Heat for
one or two minutes using a
blow pipe in oxidising flame.
Observe the colour of the
residue and draw the
inference.
Green Zn2+
Pink Mg2+
Blue Al3+
Black
It is due to
the
formation of
CoO. No
definite
indication.
COBALT NITRATE TEST (ASH TEST)
8.
EXPERIMENT
OBSERVATION
(COLOUR OF THE
FLAME)
INFERENCE
Cleanthe platinum wire by dipping it in
conc. HCl taken in a watch glass and
then heat it strongly in the flame. This
process is repeated till the wire imparts
no color to the flame. Now prepare a
paste of the mixture with conc. HCl, in a
clean watch glass. Place a small amount
of this paste on the platinum wire loop
and introduce it into the flame. Note the
color imparted to the flame.
Brick - red (not
persistent)
Ca2+
Crimson - red
(persistent)
Sr2+
Grassy - green
(Persistent)
Ba2+
Bright bluish - green Cu2+
Green flashes Zn2+
or Mn2+
Dull bluish - white Pb2+
FLAME TEST
BORAX BEAD TEST
Onheating borax the colourless glass bead fromed consists of
sodium metaborate and boric anhydride.
Na2B4O7 10H2O--∆-→ Na2B4O7 ----∆→ (NaBO2+ B2O3 )Glassy bead
On heating with a coloured salt, the glassy bead froms a coloured
metaborate in oxidising flame
CuSO4 → CuO + SO3
CuO + B2O3 → Cu(BO2)2
Copper metaborate
(Blue)
11.
Tests
The very firstessential step is to prepare a clear
and transparent solution of the salt under
investigation. For this purpose, the following
solvents are tried one after another in a
systematic order.
•Distilled water (cold or hot)
•Dilute HCl (cold or hot)
•Conc. HCl (cold or hot)
•DiluteHNO3
•Conc. HNO3
•Aqua regia (3 HCl + 1 HNO3)
12.
In case thesalt does not dissolve in a particular
solvent even on heating, try the next solvent.
Procedure
Take a small quantity of the given salt in a test
tube. Add some suitable solvent to it and shake
well. If it does not dissolve, heat the contents
gently for sometime. If it does not dissolve even
after heating for sometime, take the fresh quantity
of the salt again and treat it in a similar manner
with next solvent. The clear solution thus
obtained is labeled as Original Solution (O.S).
13.
Experiment Observation Inference
Toa small amount of solid salt taken in a test
tube, add some concentrated solution of
sodium hydroxide and heat the contents.
Characteristic
ammonical smell.
The gas evolved is NH3.
Presence of Group Zero
(NH4
+
).
Analysis of Group-Zero (NH4
+
)
Experiment Observation Inference
To a small amount of solid salt
taken in a test tube, add some
concentrated solution of sodium
hydroxide and heat the
contents.
Bring a glass rod dipped in dil.
HCl near the mouth of the test
tube.
A gas with ammonical smell is
evolved.
White fumes is produced.
The gas evolved is ammonia
which gives white fumes with
HCl due to the formation of
NH4Cl. Presence of NH4
+
is
confirmed.
Nessler’s Reagent test:
When the gas evolved in the
above test is passed through
Nessler's reagent taken in a test
tube.
Brown precipitate is formed
The brown precipitate is due to
the formation of H2N.HgO.HgI.
Presence of NH4
+
is confirmed.
Confirmation of NH4
+
Experiment Observation Inference
Toa small amount of salt solution
taken in a test tube, add dil.
hydrochloric acid. Centrifuge and
wash the precipitate.
White precipitate is
formed
The white precipitate may due
to the formation of PbCl2.
Presence of group I (Pb2+
).
Experiment Observation Inference
Boil the white precipitate with 5-10 ml of water - Precipitate dissolves - PbCl2 is
soluble in hot water - Divide the solution into three parts.
1.Cool one part of the
solution.
White crystalline precipitate
is formed.
On cooling, precipitate
settle down as PbCl2.
Presence of Pb2+
ion is
confirmed.
2. Potassium iodide test:
To the second part of the
solution, add potassium
iodide solution.
Yellow precipitate is
formed.
Yellow precipitate is due to
the formation of PbI2.
Presence of Pb2+ ion is
confirmed.
3. Potassium chromate Yellow precipitate is due to
CONFIRMATION OF Pb2+
Analysis of Group I
Experiment Observation Inference
Takeabout 2 ml of
the original solution
in a test tube. Add
some dil. HCl and
warm the contents.
Through this
solution pasS
H2S gas from the
Kipp's apparatus by
pressing the nozzle.
Formation of the
black precipitate.
The black
precipitate may be
due to the
formation of PbS or
CuS. Presence of
Group II (Pb2+
or
Cu2+
).
Formation of the
yellow precipitate.
The yellow
precipitate may be
due to the
formation of
As2S3.Presence of
ANALYSIS OF GROUP II (COPPER GROUP)
19.
Black precipitate (Pb2+
orCu2+
)
Heat the black precipitate with minimum
quantity (1-2 ml) of 50% HNO3 in a tests tube
- Precipitate dissolves.
Inference: Black precipitate dissolves in 50%
HNO3 either due to the formation of
Pb(NO3)2 or due to the formation of
Cu(NO3)2.
To one part of the above solution, add dil.
H2SO4 and alcohol
CONFIRMATION OF GROUP II CATIONS
20.
No white precipitate.To rest of the solution add
NH4OH in excess - Blue coloured solution (Cu2+
)
Inference: The blue coloured solution is due to the
formation of [Cu(NH3)4][NO3]2 by the reaction
between Cu(NO3)2 and NH4OH.
Conformation
1. Potassium ferrocyanide test:
To one part of the blue solution in a test tube add
few drops of acetic acid and potassium
ferrocyanide solution - Chocolate brown
precipitate is formed.
Inference: The chocolate brown precipitate is due
to the formation of Cu2[Fe(CN)6]. Presence of
2+
21.
2. Potassium iodidetest:
To another part of the blue solution add acetic
acid and potassium iodide solution -White
precipitate is formed in brown coloured solution.
Inference: White precipitate formed is Cu2I2.
Brown colour of the solution is due to the
formation of iodine. Presence of Cu2+
is
confirmed.
Add some Conc.HNO3 into the yellow precipitate in a
test tube –Precipitate dissolves.
Inference: The yellow residue of As2S3 is dissolved in
Conc. HNO3 forming arsenic acid, H3AsO4.
Divide the solution into two parts.
1. Ammonium molybdate test:
To a part of the solution in a test tube, add ammonium
molybdate solution and heat - Yellow precipitate is
formed.
Inference:Yellow precipitate is due to the formation of
ammonium arseno molybdate {(NH4)3AsO4.12MoO3}.
Presence of As3+
is confirmed.
24.
2. Magnesia mixturetest:
To the second part of the solution, add
NH4OH solution to make it alkaline and add
magnesia mixture - White precipitate is
formed.
Inference:The white precipitate is due to the
formation of Mg(NH4)2AsO4. Presence of
As3+
is confirmed.
Experiment Observation Inference
Takeabout 5 ml of salt
solution in a test tube
and add 4-5 drops of
conc. HNO3. Boil the
solution for some time.
Add to it about 2 g of
solid NH4Cl and boil
again.
Cool the solution by
placing the test tube in a
beaker full of water. Add
excess of ammonium
hydroxide to it and
shake.
Reddish brown
precipitate.
Reddish brown
precipitate may be due
to the formation of ferric
hydroxide, Fe(OH)3.
Presence of Group III
cation (Fe3+
).
White precipitate.
White precipitate may be
due to the formation of
aluminium hydroxide,
Al(OH)3. Presence of
Group III cation (Al3+
)
Centrifuge and separate out the precipitate.
ANALYSIS OF GROUP III (IRON GROUP)
IN CASE, FIRST AND SECOND GROUPS ARE ABSENT PROCEED FOR GROUP III WITH
THE ORIGINAL SOLUTION.
27.
Reddish Brown precipitate(Fe3+
)
White precipitate (Al3+
)
Dissolve the reddish brown ppt. in
dilute HCl, and divide the solution into
two parts.
Confirmation Confirmation
1. Pottassium ferrocynaide test:
To one part of the above solution in a
test tube add potassium ferrocyanide
solution - Prussian blue colouration.
Inference: Prussian blue colour is due
to the formation of ferric
ferrocyanide, Fe4[Fe(CN)6]3. Presence
of Fe3+
is confirmed.
1. Lake Test.
Disolve the white ppt. in dilute
hydrochloric acid. Add to it two drops
of blue litmus solution. To this, add
NH4OH dropwise till blue colour
develops - Blue precipitate floating
in colourless solution.
Inference: The precipitate formed
is aluminium hydroxide. Blue
colour absorbs on this precipitate.
Presence of Al3+
is confirmed.
CONFIRMATION OF GROUP - III CATIONS:
EXPERIMENT OBSERVATION INFERENCE
PassH2S gas through
the Ammonical
solution. {Ammonical
solution: - Take about 5
ml of salt solution in a
test tube and add 4-5
drops of conc. HNO3.
Boil the solution for
some time. Add to it
about 2 g of solid NH4Cl
and boil again. Cool the
solution by placing the
test tube in a beaker full
of water. Add excess of
ammonium hydroxide to
Black precipitate
Black precipitate may be
due to the formation of CoS
or NiS. Presence of Group
IV cation.
Buff (flesh) coloured
precipitate
Buff coloured precipitate
may be due to the
formation of MnS. Presence
of Group cation.
Dull white
precipitate
Dull white precipitate
may be due to the
formation of ZnS.
Presence of Group IV
cation.
ANALYSIS OF GROUP IV (ZINC GROUP)
IF THERE IS NO PPT. IN THE THIRD GROUP, THEN USE THE SAME AMMONICAL
SOLUTION FOR THE FOURTH GROUP.
31.
Black precipitate
(Co2+
or Ni2+
)
Observethe colour
of the original salt.
If the salt is purple
or deep violet in
colour, perform
confirmatory tests
for Co2+
and if it is
greenish, perform
confirmatory tests
for Ni2+
with the
original solution.
Buff (flesh)
coloured
precipitate
(Mn2+
)
Dull white precipitate
(Zn2+
)
To the dull white
precipitate, add some
dil. HCl and heat the
contents – The
precipitate dissolves
with the evolution of H2S
gas. Divide the solution
into two parts.
Inference: The white
precipitate of ZnS
dissolves in dil. HCl to
form ZnCl2 with the
32.
CONFIRMATION OF Co2+
1.Potassium nitrite test:
To one part of the original salt solution in a tests
tube, add ammonium hydroxide to neutralize the
solution. Add acetic acid and a crystal of
potassium nitrite. Warm the test tube - Yellow
precipitate is formed.
Inference: The yellow precipitate is due to the
formation of potassium cobalti nitrite,
K3[Co(NO2)6]. Presence of Co2+
is confirmed.
33.
2. Ammonium thiocyanateether test:
To another part of the original salt solution in a
test tube, add about 1 ml of ether. Add crystals of
ammonium thiocyanate and shake the test tube
well. Keep the solution undisturbed for some time
–Blue colouration in the ethereal layer.
Inference:Blue colour is due to the formation of
ammonium cobalti thiocyanate, (NH4)2[Co(CNS)4].
Presence of Co2+
is confirmed.
CONFIRMATION OF Ni2+
1.Dimethyl glyoxime test:
To one part of the original salt solution taken in a
test tube, add ammonium hydroxide solution and
few drops of dimethyl glyoxime - Bright rose red
precipitate is obtained.
Inference: The bright red colour is due to the
formation of Ni – dimethyl glyoxime complex;
Ni(dmgH)2. Presence of Ni2+
is confirmed.
36.
2. Sodium hydroxide- Br2test:
To another part of the original salt solution in a
test tube, add sodium hydroxide (in excess)
– Green precipitate is formed - Add bromine
water to the above ppt. Boil the content
- A black precipitate is formed.
Inference:The green precipitate is due to the
formation of Ni(OH)2.The black precipitate is
due to the formation of nickelic hydroxide,
Ni(OH)3. Presence of Ni2+
is confirmed.
CONFIRMATION OF Mn2+
1.Sodium hydroxide-Br2 test:
To one part of salt solution in a test tube, add
NaOH solution - A white precipitate is formed -
Add Bromine water to white precipitate - White
precipitate turns black or brown.
Inference: White precipitate is due to the
formation of manganese hydroxide,
Mn(OH)2.Mn(OH)2turns brown on adding
Br2 water due to the oxidation of Mn(OH)2to
MnO(OH)2. Presence of Mn2+
is confirmed.
.
39.
2. Lead peroxidetest:
To black ppt. obtained in above test
(Sodium hydroxide-Br2 test), add conc.
HNO3 and lead peroxide solution. Boil, cool
and allow to settle - Pink coloured
solution is formed.
Inference:The pink colour is due to the
formation of HMnO4. Presence of Mn2+
is
confirmed
CONFIRMATION OF Zn2+
1.Sodium hydroxide test:
To one part of the above solution in a test tube,
add sodium hydroxide (NaOH) solution dropwise
- A white precipitate is formed - Add more
NaOH to the white precipitate - The white ppt.
dissolves.
Inference: The white precipitate is due to the
formation of zinc hydroxide, Zn(OH)2 which is
soluble in excess NaOH due to the formation
of Na2ZnO2. Presence of Zn2+
is confirmed.
42.
2. Potassium ferrocyanidetest:
To the second part above solution in a
test tube, add potassium ferrocyanide
solution - White or bluish white
precipitate is formed.
Inference: The white or bluish white
precipitate is due to the formation of
Zn2[Fe(CN)6]. Presence of Zn2+
is
confirmed.
43.
(a) Sodium hydroxidetest
(b) Potassium ferrocyanide test
(c) Charcoal cavity/Cobalt nitrate
test
44.
EXPERIMENT OBSERVATION INFERENCE
Tothe original salt solution,
add 2-3 grams of solid
NH4Cl, boil and cool the
contents and add NH4OH
till the solution smells
ammonia. Then add
ammonium carbonate
solution.
Centrifuge the precipitate
and wash with water. Add
hot dilute acetic acid into
the precipitate.
Divide the solution into
White precipitate is formed
and which is dissolved in
hot dil. acetic acid..
The white precipitate may
due to the formation of
carbonates of Ba2+
, Sr2+
or
Ca2+
. These insoluble
carbonate dissolves in
acetic acid due to the
formation of soluble
acetates of Sr2+
, Ba2+
and
Ca2+
. Presence of Group V
cation.
ANALYSIS OF GROUP V (CALCIUM GROUP)
IF THE FOURTH GROUP IS ABSENT, THEN PROCEED FOR
RADICALS OF GROUP V.
45.
CONFIRMATON OF Ba2+
1.Potassium chromate test:
To one part of the above solution in a test tube,
add a few drops of potassium chromate solution -
Yellow precipitate is formed.
Inference : The yellow precipitate is due to the
formation of barium chromate, BaCrO4. Presence
of Ba2+
is confirmed.
.
46.
2. Flame test:
Takea small amount of the salt in a watch
glass and add few drops of conc. HCl. Mix
the contents well to make a paste. Dip a
cleaned platinum wire into this paste and
introduce the wire into the non-luminous
flame. Note the colour imparted on the
flame -Grassy green flame.
Inference:Presence of Ba2+
is confirmed
CONFIRMATION OF Sr2+
1.Ammonium sulphate test:
To second part of the above solution in a
test tube, add 1 ml of ammonium sulphate
solution and warm the contents - White
precipitate is formed.
Inference: The white precipitate is due to
the formation of strontium sulphate, SrSO4.
Presence of Sr2+
is confirmed.
.
49.
2. Flame test:
Takea small amount of the salt in a watch
glass and add few drops of conc. HCl. Mix
the contents well to make a paste. Dip a
cleaned platinum wire into this paste and
introduce the wire into the non-luminous
flame. Note the colour imparted on the
flame - Crimson red flame
Inference:Presence of Sr2+
is confirmed
CONFIRMATION OF Ca2+
1.Ammonium oxalate test:
To third part of the above solution in a test tube,
add 1 ml of drops of ammonium oxalate solution.
Add a little ammonium hydroxide to it and scratch
the sides of the test tube with a glass rod - White
precipitate is formed.
Inference: The white precipitate is due to the
formation of calcium oxalate, CaC2O4. Presence
of Ca2+
is confirmed.
52.
2. Flame test:
Takea small amount of the salt in a watch
glass and add few drops of conc. HCl. Mix
the contents well to make a paste. Dip a
cleaned platinum wire into this paste and
introduce the wire into the non-luminous
flame. Note the colour imparted on the
flame - Brick red flame.
Inference: Presence of Ca2+
is confirmed.
EXPERIMENT OBSERVATION INFERENCE
1.Ammonium Phosphate test:
To a part of the original salt solution in a test
tube, add some solid NH4Cl and solution of
NH4OH in slight excess. Then add ammonium
phosphate solution and rub the sides of the
test-tube with a glass rod.
A white
precipitate is
formed.
The white
precipitate is due
to the formation of
magnesium
ammonium
phosphate,
Mg(NH4)PO4.
Presence of Mg2+
is
confirmed.
2.Cobalt nitrate/Charcoal cavity test:
Take a charcoal box with a small cavity in it. Take a small
amount of salt in a watch glass. Add solid sodium carbonate
whose quantity is 2 time that of the salt into the cavity. Put this
mixture in the cavity. Add a drop of water to the mixture. Then
direct the reducing flame of Bunsen burner on the cavity by
means of blowpipe. Heat strongly for sometime - A white
residue is formed.
Put one or two drops of cobalt nitrate solution on the white
residue left after the cavity in the charcoal cavity test. Direct
oxidizing flame into the mixture using blow pipe and observe
Pink mass is
formed.
Pink mass is due to
the formation of
MgO.CoO. Presence
of Mg2+
is
confirmed.
ANALYSIS OF GROUP VI (MAGNESIUM GROUP)
Most read
![No white precipitate. To rest of the solution add
NH4OH in excess - Blue coloured solution (Cu2+
)
Inference: The blue coloured solution is due to the
formation of [Cu(NH3)4][NO3]2 by the reaction
between Cu(NO3)2 and NH4OH.
Conformation
1. Potassium ferrocyanide test:
To one part of the blue solution in a test tube add
few drops of acetic acid and potassium
ferrocyanide solution - Chocolate brown
precipitate is formed.
Inference: The chocolate brown precipitate is due
to the formation of Cu2[Fe(CN)6]. Presence of
2+](https://image.slidesharecdn.com/pptofsalt2-260703040745-80178103/85/Inorganic-salt-analysis-or-Qualitative-analysis-20-320.jpg)
![Reddish Brown precipitate (Fe3+
)
White precipitate (Al3+
)
Dissolve the reddish brown ppt. in
dilute HCl, and divide the solution into
two parts.
Confirmation Confirmation
1. Pottassium ferrocynaide test:
To one part of the above solution in a
test tube add potassium ferrocyanide
solution - Prussian blue colouration.
Inference: Prussian blue colour is due
to the formation of ferric
ferrocyanide, Fe4[Fe(CN)6]3. Presence
of Fe3+
is confirmed.
1. Lake Test.
Disolve the white ppt. in dilute
hydrochloric acid. Add to it two drops
of blue litmus solution. To this, add
NH4OH dropwise till blue colour
develops - Blue precipitate floating
in colourless solution.
Inference: The precipitate formed
is aluminium hydroxide. Blue
colour absorbs on this precipitate.
Presence of Al3+
is confirmed.
CONFIRMATION OF GROUP - III CATIONS:](https://image.slidesharecdn.com/pptofsalt2-260703040745-80178103/85/Inorganic-salt-analysis-or-Qualitative-analysis-27-320.jpg)
![CONFIRMATION OF Co2+
1. Potassium nitrite test:
To one part of the original salt solution in a tests
tube, add ammonium hydroxide to neutralize the
solution. Add acetic acid and a crystal of
potassium nitrite. Warm the test tube - Yellow
precipitate is formed.
Inference: The yellow precipitate is due to the
formation of potassium cobalti nitrite,
K3[Co(NO2)6]. Presence of Co2+
is confirmed.](https://image.slidesharecdn.com/pptofsalt2-260703040745-80178103/85/Inorganic-salt-analysis-or-Qualitative-analysis-32-320.jpg)
![2. Ammonium thiocyanate ether test:
To another part of the original salt solution in a
test tube, add about 1 ml of ether. Add crystals of
ammonium thiocyanate and shake the test tube
well. Keep the solution undisturbed for some time
–Blue colouration in the ethereal layer.
Inference:Blue colour is due to the formation of
ammonium cobalti thiocyanate, (NH4)2[Co(CNS)4].
Presence of Co2+
is confirmed.](https://image.slidesharecdn.com/pptofsalt2-260703040745-80178103/85/Inorganic-salt-analysis-or-Qualitative-analysis-33-320.jpg)
![2. Potassium ferrocyanide test:
To the second part above solution in a
test tube, add potassium ferrocyanide
solution - White or bluish white
precipitate is formed.
Inference: The white or bluish white
precipitate is due to the formation of
Zn2[Fe(CN)6]. Presence of Zn2+
is
confirmed.](https://image.slidesharecdn.com/pptofsalt2-260703040745-80178103/85/Inorganic-salt-analysis-or-Qualitative-analysis-42-320.jpg)
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