chemical test for alkanes and alkenes

[pkij]

I have to prepare a prac to test for alkanes and alkenes. This asks for bromine dissolved in trichloroethane. Does bromine water work the same for the tests as I have some of that in stock. Any hints and help would be appreciated.

Thanks

[Robb]

Hi pkij,

Bromine certainly is the test for the of Alkenes or double bonded hydrocarbons, (any for that matter), (within reason of course)....

Pure Bromine is best but working with this substance requires great professional training (under these conditions it is quite safe to use.

Bromine Water will work but remember this... There will be a small amount of water remaining in the reaction vessel (test tube) as water will not mix (it is imiscible with water) so sometimes students question this but this answer you give them won't jeopardise there prac test.

This is mainly as the Br is being used in the breaking of the double bond in the Alkene the liquid becomes clear leaving a clear water layer and a clear Di-Bromo Alkene layer.

Students can't use Pure Bromine but Br Water is suffice. After the prac exam you could demonstrate to them what the Pure Br actually does in the presence of both Alkanes and Alkenes.

I hope this answers your question..

Cheers,

Robb.....