How to tell the difference between octane-1-ol and oct-1-ene?
Alkene is best characterized, then, by its property
of decolorizing both a solution of bromine in carbon tetrachloride  and
a cold, dilute, neutral permanganate solution (the Baeyer test). Both
tests are easily carried out; in one, a red color disappears, and in the other, a purple color disappears and is replaced by brown manganese dioxide.