Question

the reagent change it colour from red to colourless on passing unsaturated organic compound through it.
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Answer 1

Answer:

TESTS FOR HYDROCARBONS - DEFINITION

To test whether the hydrocarbon is unsaturated or saturated Bromine test is performed, which involves the addition of bromine water to the hydrocarbon in question; unsaturated hydrocarbons decolourised the bromine water, whereas saturated hydrocarbon will not decolourise it.

BROMINE WATER TEST - DEFINITION

Bromine water which is brownish-red on reaction with alkene or alkyne i.e. unsaturated compounds forms di or tetra halo compounds which is colorless in nature.while saturated compounds i.e. alkane do not react with bromine water and color of bromine water remain same.

C

2

H

6

+Br

2

→C

2

H

6

+Br

2

C

2

H

4

+Br

2

→C

2

H

4

Br

2

TEST OF ETHYLENE - EXAMPLE

Alkenes react with pure liquid bromine, or with a solution of bromine . The double bond breaks, and a bromine atom becomes attached to each carbon. The bromine loses its original red-brown colour to give a colourless liquid..