Testing for unsaturation with bromine on a microscale

In this practical, students use reverse disproportionation to produce a source of bromine from bromate ions, bromide ions and acid. They extract the bromine into hexane in a plastic pipette and decant the resulting solution into a well-plate.

Students can then test for unsaturated hydrocarbons, mixing the bromine solution with organic compounds such as cyclohexane, cyclohexene and limonene. Unsaturated compounds rapidly decolourise the bromine.