Bromine water is an orange solution of bromine. It becomes colourless when it is shaken with an alkene. Alkenes can decolourise bromine water, but alkanes cannot. The slideshow shows this process.

The rapid disappearance of the amber color of the bromine at room temperature is characteristic of reaction with alkenes. (colorless) (purple) (colorless) (brown ppt.) Reaction of an alkene with ...

This causes a smoky flame. Alkenes have a functional group C=C – the part of the molecule that takes part in reactions. Alkanes, in contrast, do not have a functional group and are less reactive ...

Environmental scientists find that pan-frying leads to peak VOC concentrations of 260ppb, versus 20ppb for air-frying ...