How to convert ethane to ethene

Bromine water is an aqueous solution of bromine in water.


Since bromine is only sparingly soluble in water, a brown-colored, dilute bromine solution is created.


Bromine water is used in the laboratory for the rapid detection of C = C double bonds in organic compounds such as alkenes. If an organic compound is introduced as a gas (e.g. ethene) into bromine water or shaken as a liquid with bromine water, whereby the solution becomes colorless, the sample substance contains at least one C = C double bond. This evidence is based on an electrophilic addition. The bromide ions, which are positively and negatively charged as a result of polarization and heterolytic cleavage, form bonds with the p electrons that were previously involved in the double bond.

Bromine adds to ethene. 1,2-Dibromoethane is formed.

The reaction of bromine water with an alkane takes place only with a catalyst and / or under high-energy light. The bromine water is also decolorized, but HBr is also formed, since the reaction mechanism is now a radical substitution. It is very easy to differentiate between alkanes and alkenes.

Substitution reaction of ethane and bromine. Bromethane and hydrogen bromide are formed.

safety instructions

The escaping bromine fumes are very poisonous. They must not be inhaled as the bromine fumes corrode the alveoli and the airways.

For details see article Brom

Category: Chemical Solution