Mr Azlan SK 026 Organic Chemistry
Methods to Distinguish Organic Compounds
Chemical tests/reactions for
identification/recognition Purpose
purposes
Reaction with Br2 in CH2Cl2
To detect the presence of carbon-carbon double bond. Can be used to distinguish alkene with other classes
Reaction with Br2 in H2O
of compounds.
Baeyer’s Test
Alkene Ozonolysis
Oxidative cleavage Reaction with [Not used as a chemical test] Used to determine the position of carbon-carbon double bond.
hot, acidified
KMnO4
Used to distinguish different classes of alcohols. Cannot be used as a test to differentiate alcohol with other
Lucas Test
classes of compounds.
Alcohol
Hydroxy Used to detect the presence of methyl carbinol (usually in order to determine the position of hydroxyl group
Iodoform test
compounds in a molecule). Cannot be used as a test to differentiate alcohols with other classes of compounds.
Reaction with FeCl3
Phenol Used to identify phenol. Can be used to distinguish phenol with other classes of compounds
Reaction with excess bromine water
Used to identify the presence of carbonyl group in aldehydes and ketones. Can be used to distinguish
Brady’s Test
carbonyls with other classes of compounds. Cannot be used to distinguish aldehydes from ketones.
Used to detect aliphatic aldehydes (gives positive results). Aromatic aldehydes and ketones give negative
Fehling’s test results. Cannot be used to distinguish aldehydes/ketones from other classes of compounds. Can be used to
Carbonyl distinguish aliphatic aldehydes from ketones.
Used to distinguish aldehydes (both aromatic and aliphatic) from ketones. Cannot be used to distinguish
Tollen’s test
aldehydes/ketones from other classes of compounds.
Used to distinguish aldehydes from ketones. Not advisable to use this test in an exam as the chemical
Schiff’s test
equation is complicated and outside the scope of the syllabus.
Used to distinguish between 1˚, 2˚, and 3˚ amines. Cannot be used to differentiate amines with other
Amine Hinsberg’s test
classes of compounds.
Used to distinguish between 1˚, 2˚, and 3˚ aliphatic amines. Cannot be used to differentiate amines with
Amine Nitrous acid test
Amines other classes of compounds.
Used to detect the aniline. Similar reaction as seen with Phenol and Br2 in water. Can be used to
Aniline Br2 in H2O differentiate between aniline and other compounds except for phenol as both displays the same
observation.
Methods to Distinguish Organic Compounds
Chemical tests/reactions for
identification/recognition Purpose
purposes
Reaction with Br2 in CH2Cl2
To detect the presence of carbon-carbon double bond. Can be used to distinguish alkene with other classes
Reaction with Br2 in H2O
of compounds.
Baeyer’s Test
Alkene Ozonolysis
Oxidative cleavage Reaction with [Not used as a chemical test] Used to determine the position of carbon-carbon double bond.
hot, acidified
KMnO4
Used to distinguish different classes of alcohols. Cannot be used as a test to differentiate alcohol with other
Lucas Test
classes of compounds.
Alcohol
Hydroxy Used to detect the presence of methyl carbinol (usually in order to determine the position of hydroxyl group
Iodoform test
compounds in a molecule). Cannot be used as a test to differentiate alcohols with other classes of compounds.
Reaction with FeCl3
Phenol Used to identify phenol. Can be used to distinguish phenol with other classes of compounds
Reaction with excess bromine water
Used to identify the presence of carbonyl group in aldehydes and ketones. Can be used to distinguish
Brady’s Test
carbonyls with other classes of compounds. Cannot be used to distinguish aldehydes from ketones.
Used to detect aliphatic aldehydes (gives positive results). Aromatic aldehydes and ketones give negative
Fehling’s test results. Cannot be used to distinguish aldehydes/ketones from other classes of compounds. Can be used to
Carbonyl distinguish aliphatic aldehydes from ketones.
Used to distinguish aldehydes (both aromatic and aliphatic) from ketones. Cannot be used to distinguish
Tollen’s test
aldehydes/ketones from other classes of compounds.
Used to distinguish aldehydes from ketones. Not advisable to use this test in an exam as the chemical
Schiff’s test
equation is complicated and outside the scope of the syllabus.
Used to distinguish between 1˚, 2˚, and 3˚ amines. Cannot be used to differentiate amines with other
Amine Hinsberg’s test
classes of compounds.
Used to distinguish between 1˚, 2˚, and 3˚ aliphatic amines. Cannot be used to differentiate amines with
Amine Nitrous acid test
Amines other classes of compounds.
Used to detect the aniline. Similar reaction as seen with Phenol and Br2 in water. Can be used to
Aniline Br2 in H2O differentiate between aniline and other compounds except for phenol as both displays the same
observation.
