The document describes experiments conducted to qualitatively analyze an unknown organic sample. Through solubility tests, the sample was found to be insoluble in water and NaOH, but soluble in HCl and ether, indicating it is an amine. Elemental analysis detected nitrogen but no sulfur or halogens. Tests for functional groups confirmed the presence of an aromatic primary amine. The conclusion is that the unknown sample is aniline.

2. Qualitative Analysis of an Unknown Sample.
Mrs Chanda Ranjan
Department of Pharmaceutical Chemistry
The Oxford College of Pharmacy, Bangalore

3. Learning outcome:
Understand how to conduct –
1. Preliminary investigation
2. Solubility Analysis
3. Elemental detection
4. Functional group Analysis
5. Confirmatory test of any unknown compound in the lab.
LearningOutcome

4. Experiment Observation Inference
Physical appearance and Color
Odor
Solubility Characteristics
Take about 0.1 g of solid (0.5 ml of liquid)
each in four separate test tubes and add 3
ml each of
a) cold and hot water
b) 5% HCL
c) 5% NaOH.
d) Ether
Fishy
Light yellow
colored liquid
@Chanda Ranjan
4
Insoluble in Water
Insoluble in 5% NaOH
Soluble in 5% HCl
Soluble in Ether
PreliminaryInvestigation
Alcohol , ketone , aldehyde, ester,
phenol, amines may be present.
Amine

5. According to the solubility of the organic compound there are 7 groups
Group IIGroup I Group IVGroup III Group V Group VIIGroup VI
Soluble in
water
and ether
Soluble in
water and
insoluble in
ether
Insoluble in
water, soluble
in ether and
readily
soluble in
Bases
(5% NaOH)
Soluble in
ether, insoluble
in water, but
soluble in
diluted acid
(5% HCl)
N and S is absent
Some Phenols
Alcohols
Aldehydes
Ketones and
Acids having
Low MW (upto
5 to 6 carbon
atoms
Sugars
Glucose
Urea
Thiourea
Acids, Phenols
Imides
Amines
Aromatic-N-
heterocycles
Unsaturated
hydrocarbons
Aldehydes,
ketones,
esters, ethers
anhydrides,
acyl halides
Hydrocarbons
Halogen
Hydrocarbons
Cyclic Paraffin
Amides
Nitro
Compounds,
Nitriles
Soluble only in
conc H2SO4
Insoluble only
in conc H2SO4
Contains
N and S
And all the
solubility test
fails
SolubilityAnalysis

6. 6
PreliminaryInvestigation
Experiment Observation Inference
Physical appearance and Color Carbohydrate, acid , phenol, amine ,
higher hydrocarbon may be present
Odor Phenol, cresol.
Solubility Characteristics
Take about 0.1 g of solid (0.5 ml of liquid)
each in four separate test tubes and add 3
ml each of
a) cold and hot water
b) 5% HCL
c) 5% NaOH.
d) Ether
Insoluble in Water
Insoluble in 5% NaOH
Soluble in 5% HCl
Soluble in Ether
Compound belongs to Group IV
That comprises:
Amines,
Hydrazines

7. Experiment Observation Inference
Test for acidic or basic nature
Dissolve about 0.5 ml of liquid in water and
place one drop of the solution on blue and red
litmus each.
Dissolve 0.5 gm of the given solid into 2ml of
5% NaHCO3 solution
Red Litmus turned blue
Compound is basic in nature,
Action of 5 % NaHCO3
Insoluble with no characteristic
changes.
Compound can be Phenols
or amines
Red Litmus Paper
PreliminaryInvestigation

8. Test for aromatic or aliphatic nature
a) Take a small quantity of the given organic
compound on a nickel spatula and ignite (heat
strongly)
b) Add 1 ml of conc HNO3 and 1 ml of conc.
H2SO4 to a small quantity of the substance.
Heat well and cool. Pour into a beaker of
water. (NITRATION TEST)
1 ml of
conc HNO3
1 ml of
conc. H2SO4
Water
Yellow color is observed
Sooty flame Presence of aromatic
compound
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Presence of aromatic
compound
Pour
PreliminaryInvestigation

9. Test for saturation or unsaturation
A) Bromine water test
Add 2 or 3 drops of saturated bromine water to
the substance and shake well.
B) Baeyer’s Reagent test
Add 1 ml of water and 2 drops of Baeyer's
reagent (alkaline potassium permanganate) to a
small quantity of the substance.
2 drops of Br2 water
shaken
The color of bromine
is not discharged
2 drops of Baeyer's reagent
shaken
Pink color is not
discharged
Compound is saturated
Compound is saturated
9
PreliminaryInvestigation

10. Experiment Observation Inference
Test with neutral FeCl3 solution
Add 1 gm of neutral ferric chloride solution to a
small quantity of the compound.
1ml of Ferric
Chloride
No Purple color formed
Phenolic group is absent
PreliminaryInvestigation

11. Procedure for the preparation of sodium fusion extract or Lassaigne's Extract.
• A small piece of dry sodium in a fusion tube is taken.
• Heat the tube slightly on a Bunsen burner so that the sodium melts and looks red hot.
• Add a pinch of the sample.
• Heat it slowly to start with so that the compound reacts with sodium metal and continue heating till
it becomes red hot.
• Plunge the red hot tube into a china dish containing distilled water.
• Crush the contents with a glass rod and heat to boiling point and concentrate the solution.
• Filter it with the help of funnel and filter paper.
• The filtrate is called Lassaigne's Extract.
ElementalAnalysis

12. Detection of Elements
Preparation of Sodium fusion extracts tests or lassaigne's tests
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ElementalAnalysis

13. Experiment Observation Inference
a) Test for nitrogen
To 1 ml of the sodium fusion extract add 1 ml of
ferrous sulphate solution. Add about 1 ml of dilute
sulphuric acid.
b) Test for Sulphur
To 1 ml of the sodium fusion extract add 3 drops of
freshly prepared sodium nitroprusside solution. To
another portion of the extract add 4 drops of lead
acetate solution.
c) Test for Halogen
To another portion of the extract add dilute nitric acid
to acidify and silver nitrate solution (1ml)
d) Test for Nitrogen and Sulphur together
Take a small portion of the sodium fusion extract and
add 2 ml of dil HCl and 1ml of FeCl3 solution. Shake
well.
1 ml of ferrous sulphate solution
shake
Dark greenish grey
ppt of ferrous hydroxide
is formed
1 ml of dilute sulphuric acid.
Formation of Prussian
blue ppt
Nitrogen is present
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ElementalAnalysis

14. Experiment Observation Inference
a) Test for nitrogen
To 1 ml of the sodium fusion extract add 1 ml of
ferrous sulphate solution. Add about 1 ml of dilute
sulphuric acid.
b) Test for Sulphur
1. To 1 ml of the sodium fusion extract add 3 drops of
freshly prepared sodium nitroprusside solution
2. To the sample add 1 ml of dilute acetic acid and
few drops of lead acetate solution
c) Test for Halogen
To another portion of the extract add dilute nitric acid
to acidify and silver nitrate solution (1ml)
d) Test for Nitrogen and Sulphur together
Take a small portion of the sodium fusion extract and
add 2 ml of dil HCl and 1ml of FeCl3 solution. Shake
well.
shake
3 drops of freshly prepared
sodium nitroprusside solution
No appearance of
brilliant purple color
1 ml of dil acetic acid
+
Few drops of lead acetate
No appearance of
black ppt
Sulphur is Absent
ElementalAnalysis

15. Experiment Observation Inference
a) Test for nitrogen
To 1 ml of the sodium fusion extract add 1 ml of
ferrous sulphate solution. Add about 1 ml of dilute
sulphuric acid.
b) Test for Sulphur
To 1 ml of the sodium fusion extract add 3 drops of
freshly prepared sodium nitroprusside solution. To
another portion of the extract add 4 drops of lead
acetate solution.
c) Test for Halogen
To another portion of the extract add dilute nitric acid
to acidify and silver nitrate solution (1ml)
d) Test for Nitrogen and Sulphur together
Take a small portion of the sodium fusion extract and
add 2 ml of dil HCl and 1ml of FeCl3 solution. Shake
well.
shake
1ml of dil nitric acid
+
1ml of silver nitrate solution
No white or yellow
ppt formed
Absence of Halogens
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ElementalAnalysis

16. Experiment Observation Inference
a) Test for nitrogen
To 1 ml of the sodium fusion extract add 1 ml of
ferrous sulphate solution. Add about 1 ml of dilute
sulphuric acid.
b)Test for Sulphur
To 1 ml of the sodium fusion extract add 3 drops of
freshly prepared sodium nitroprusside solution. To
another portion of the extract add 4 drops of lead
acetate solution.
c) Test for Halogen
To another portion of the extract add dilute nitric acid
to acidify and silver nitrate solution (1ml)
d) Test for Nitrogen and Sulphur together
Take a small portion of the sodium fusion extract and
add 2 ml of dil HCl and 1ml of FeCl3 solution. Shake
well.
shake
2 ml of dil HCl
+
1ml of FeCl3 solution
No blood red color formation
Nitrogen and sulphur
both are absent
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ElementalAnalysis

17. Conclusion drawn:
• After the Preliminary investigation, elemental analysis and solubility analysis.
• The compound showed positive saturated aromatic behavior and is basic in nature.
• The compound has presence of special elements nitrogen but shows negative result to sulphur and
halogens.
• The compound is insoluble in water, 5% NaOH, but soluble in 5% HCl and ether which shows
that the compound belongs to Group IV.
• Hereby I am attaching the link which has the description about the different groups according to
solubility data https://youtu.be/GVnOX9GmXY0.
• As we know that Group IV compounds are Amines.

18. Experiment Observation Inference
Test for Amines
Carbylamine Test
Take 0.2 gm of KOH and add 2 ml of ethanol. Warm
the Test tube. To this add a few drops of chloroform
and small amount of the sample. Warm gently.
2 ml of ethanol
+
0.2 gm of KOH
When the solution
mixed together
Primary amine is present
CHCl3
+ small amount of sample
Offensive smell
FunctionalGroupAnalysis

19. Experiment Observation Inference
Test for Amines
Azo Dye Test
Take 0.5 gm of the sample and add 3 ml of conc HCl
and then cool in ice. To the cold solution add aqueous
solution of sodium nitrite dropwise with shaking. To
this add 0.5 gm of beta naphthol in sodium hydroxide
solution.
3ml HCl
Cooled
in ice
Aq sol of
sodium nitrite
+
0.5 gm beta naphthol in NaOH
Orange or Red ppt formed
Aromatic primary
amine is present
FunctionalGroupAnalysis

20. Conclusion
The given compound is Aniline
Thank You