Names:____________________________ Course:_____________________

Lab. Course: _______________________ Lab No.:____________________

Date: __________________________ Score:________________(50/50)__

Experiment 1:

Tests for the functional groups

Objective

To identify the functional groups present in an organic compound through;

● Tests for Unsaturatuion

● Tests for Alcoholic Group
● Tests for Phenolic Group

Introduction

Organic chemistry is the branch of chemistry that deals with the structure, properties and
reactions of compounds that contain carbon. The objects of study in organic chemistry include
hydrocarbon, compounds containing carbon and hydrogen and the compositions based on carbon
but containing other elements. Organic compound form the basis of earthly life and their range of
application is enormous. They are the main constituents of drugs, petrochemicals, paints, food,
plastics, explosive materials etc. Organic compounds contain only carbon and hydrogen are
called Hydrocarbons. Hydrocarbons can be classified into two: Saturated Hydrocarbons
(Alkanes) and Unsaturated Hydrocarbons (Alkenes & Alkynes)
Hydrocarbons that contain carbon-carbon single bonds are called saturated hydrocarbons.
They are also called Paraffins or Aliphatic Hydrocarbons. They may have straight chain,
branched or ring structure. Hydrocarbons that contain carbon-carbon double bond or triple bond
are called unsaturated hydrocarbons.
Alkenes: Aliphatic hydrocarbons that contain carbon-carbon double bond are called alkenes.
One σ (sigma) bond and one π (pi) bond constitute a double bond.

Alkynes: Aliphatic hydrocarbons that contain carbon-carbon triple bond are called alkynes. A
triple bond contains one σ (sigma) bond and two π (pi) bonds.

The number of π bonds present in a molecule of an organic compound is termed as the

Degree of Unsaturation.

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 The compounds that are derived from hydrocarbons by replacing one or more hydrogen
atoms by other atoms or groups of atoms are called derivatives of hydrocarbons or families.
The atom or group of atoms that replaces hydrogen atoms from hydrocarbon are called
functional groups. They may be –OH, -COOH, -CO, -CHO, -Cl, -COCl, -COOR etc. Functional
groups are responsible for the characteristics of a molecule.

 
Functional groups and their identification tests.

Tests for Unsaturation

There are two tests for determining unsaturation in an organic compound.

1. Bromine Test: In this test, the orange-red colour of bromine solution disappears when it is
added to an unsaturated organic compound (unsaturated hydrocarbon).

Prepared by: Efefany Jane H. Jumarito

2. Baeyer’s Test (Alkaline KMnO4 Test): In this test, pink colour of KMnO4 disappears, when
alkaline KMnO4 is added to an unsaturated hydrocarbon. The disappearance of pink colour may
take place with or without the formation of brown precipitate of MnO2.

Tests for Alcoholic Group

Alcohols are compounds in which the hydroxyl group (-OH) is linked to aliphatic carbon
chain or in the side chain of an organic compound. Depending upon the number of hydroxyl
group, alcohols are classified as mono (contain only one –OH group), di (contain two –OH
groups) and trihydric (contains three –OH groups).

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 Alcohols are further classified as primary (1°), secondary (2°) and tertiary (3°) according to the
–OH group is attached to the primary, secondary and tertiary carbon atoms respectively.

The alcoholic group can be detected by the following tests:

1. Sodium metal test: Alcohols react with active metals like sodium and liberate hydrogen gas
that can be observed in the form of effervescence.

2. Ester test: Alcohols react with carboxylic acids to form fruity smelling compounds called
esters. The reaction between alcohol and carboxylic acid is called esterification and is catalysed
by an acid such as concentrated sulphuric acid.

3. Ceric ammonium nitrate test: Alcohols react with ceric ammonium nitrate to form a red
coloured alkoxy cerium (IV) compound.

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4. Acetyl chloride test: Alcohols react with acetyl chloride to form esters and gives out hydrogen
chloride gas. The hydrogen chloride formed gives white fumes of ammonium chloride with
ammonium hydroxide.

5. Iodoform test: This test is given by acetaldehyde, all methyl ketones and all alcohols
containing CH3-CH-OH group. When alcohol is warmed with sodium hydroxide solution and
iodine, a yellow precipitate of iodoform is formed.

Tests for Phenolic group

Phenols are compounds containing a hydroxyl group attached to an aromatic ring. The
simplest phenol is C6H5OH that is solid in winter and liquid in summer. Phenols are generally
colourless but are coloured when it comes in contact with air due to oxidation. Other examples of
phenols are: o-cresol, m-cresol, p-cresol, quinol, catechol, resorcinol etc.

Prepared by: Efefany Jane H. Jumarito

The phenolic group can be detected by the following tests:

1. Litmus test: Phenol is a weak acid, it gives red colour with litmus paper. The dissociation of
phenol in water is represented as follows:

2. Ferric chloride test: Phenol reacts with ferric ions to form violet coloured complex.

3. Liebermann’s test: When phenol is treated with sodium nitrite in the presence of concentrated
sulphuric acid, deep blue or green colour is produced. The blue or green colour changes to red or
brown colour on treatment with water. The red colour is due to the formation of indophenol. The
red colour again changes to blue or green by the addition of strong alkali. The blue or green
colour is due to the formation of indophenols anion.

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 4. Phthalein Dye test: Phenol on heating with phthaleic anhydride in the presence of sulphuric
acid produces phenolphthalein, which is colourless. Phenolphthalein gives pink colour on
treating with alkali.

Procedure
Tests for Unsaturation

Experiment Procedure Observation Inference

1. Take a small amount of organic

compound.
2. Dissolve up in about 2 ml of
Bromine Test distilled water in a test tube
3. Add few drops of bromine water to
it and shake well.

1. Take a small amount of organic

compound.
Baeyer's Test
2. Dissolve up in about 2 ml of
(Alkaline .
distilled water in a test tube
KMnO4 Test)
3. Add few drops of alkaline solution
of KMnO4 to it and shake well.

Tests for Alcoholic Group

Experiment Procedure Observation Inference

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 1. Take 1 ml of the given liquid in a dry test tube.
Sodium metal
Test 2. Add 1gram of anhydrous calcium sulphate and
shake well to remove water. .
3. Filter the liquid into another clean dry test tube.
 
4. Add a small piece of sodium metal.

1. Take 1 ml of the given liquid in a clean dry test

tube.

2. Add 1 ml glacial acetic acid.

3. Add 2-3 drops of concentrated sulphuric acid.

Ester Test .
4. Warm the mixture on a water bath for about 10
minutes.

5. Pour it into about 20 ml of cold water taken in a

beaker and smell.

Ceric 1. Take 1 ml of the given liquid in a clean dry test

ammonium tube 2 Add few drops of ceric ammonium nitrate .
nitrate Test reagent and shake it well.

1. Take 2 ml of the given liquid in a clean dry test

tube.

2. Add 1 g of anhydrous calcium sulphate and

shake well to remove water.
Acetyl chloride
3. Filter the liquid into another clean dry test tube. .
Test
4. To the filtrate, add 2-3 drops of acetyl chloride.
5. Shake the test tube well and bring a glass rod
dipped in ammonium hydroxide solution near the
mouth of the test tube.

Distinguishing Tests for Primary, Secondary and tertiary Alcohols

Experiment Procedure Observation Inference

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 1. Take 1 ml of dry alcohol in
a clean dry test tube.

 Lucas Test 2. Add 8-10 drops of Lucas

reagent.

3. Shake the mixture well.

Tests for Phenolic Group

Experiment Procedure Observation Inference

1. Place a drop of the given liquid (or a crystal if

Litmus Test
solid) on a moist blue litmus paper.

1. Take 1 ml of neutral ferric chloride solution in

Ferric chloride a clean test tube.
Test 2. Add 2-3 drops of the given liquid (or crystal is
solid).

1. Take a small quantity of sodium nitrite in a

clean dry test tube

2. Add 1 ml of the given liquid (or crystal if

solid).

3. Heat the test tube very gently for half a minute

Liebermann’s and allow it to cool.
Test
4. Add about 1 ml of concentrated sulphuric acid
and shake the test tube to mix the contents.

5. Add distilled water carefully to the test tube.

6. Add excess of sodium hydroxide solution to

the test tube.

Phthalein Dye 1. Take 1 ml of the given liquid in a clean dry

Test test tube (or crystal if solid).  

2. Add 1-2 drops of concentrated sulphuric acid.

Prepared by: Efefany Jane H. Jumarito

 3. Heat the test tube for about 1 minute in an oil
bath.

4. Cool and pour the reaction mixture carefully

into a beaker containing 15 ml of diluted sodium
hydroxide solution.

Conclusion (6pts)

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Prepared by: Efefany Jane H. Jumarito