How is bromine solution useful in testing of unsaturated compounds ? Explain the science behind it.
n organic chemistry, the bromine test is a qualitative test for the presence of unsaturation (carbon-to-carbon double or triple bonds) and phenols.
An unknown sample is treated with a small amount of elemental bromine in an organic solvent, being as dichloromethane or carbon tetrachloride. Presence of unsaturation and/or phenol in the sample is shown by disappearance of the deep brown coloration of bromine when it has reacted with the unknown sample. The formation of a brominated phenol in form of a white precipitate indicates that the unknown was a phenol. The more unsaturated an unknown is, the more bromine it reacts with, and the less coloured the solution will appear.
Should the brown colour not disappear, possibly due to the presence of an alkene which does not react, or reacts very slowly with, bromine, the potassium permanganate test should be performed, in order to determine the presence or absence of the alkene.The iodine value is a way to determine the presence of unsaturation quantitatively.
The bromine test is a simple qualitative test.
A bromine solution is used to test for unsaturation. On its own bromine solution is orange in colour.
When an alkene (e.g. ethene) is added to a bromine solution, the orange colour disappears resulting in a colourless solution.
This is because the bromine in the solution has reacted with the alkene, forming a new (colourless) compound.
This is a useful test to distinguish alkenes from alkanes because alkanes do not react with bromine solution, hence its orange colour remains visible.
n organic chemistry, the bromine test is a qualitative test for the presence of unsaturation (carbon-to-carbon double or triple bonds) and phenols.
An unknown sample is treated with a small amount of elemental bromine in an organic solvent, being as dichloromethane or carbon tetrachloride. Presence of unsaturation and/or phenol in the sample is shown by disappearance of the deep brown coloration of bromine when it has reacted with the unknown sample. The formation of a brominated phenol in form of a white precipitate indicates that the unknown was a phenol. The more unsaturated an unknown is, the more bromine it reacts with, and the less coloured the solution will appear.
Should the brown colour not disappear, possibly due to the presence of an alkene which does not react, or reacts very slowly with, bromine, the potassium permanganate test should be performed, in order to determine the presence or absence of the alkene.The iodine value is a way to determine the presence of unsaturation quantitatively.
The bromine test is a simple qualitative test.
A bromine solution is used to test for unsaturation. On its own bromine solution is orange in colour.
When an alkene (e.g. ethene) is added to a bromine solution, the orange colour disappears resulting in a colourless solution.
This is because the bromine in the solution has reacted with the alkene, forming a new (colourless) compound.
This is a useful test to distinguish alkenes from alkanes because alkanes do not react with bromine solution, hence its orange colour remains visible.
