When bromine is added to an alkane, why does the solution become colourless? When bromine is added to an alkene, why does the solution remain brown?

1 Answer
Feb 19, 2018

Answer:

The change in structure from a diatomic #Br_2# to an ionic or polar covalent #Br-C-R# bond changes the light adsorption/reflection wavelength.

Explanation:

You have the reactions reversed. Bromine reacts with ALKENES, not Alkanes.

This effect is also seen with other halogens, most notably Iodine.