Potassium permanganate is a potent oxidant, and would oxidize ethyl alcohol up to acetic acid (and maybe beyond this!). The reduction product is MnO_2, and the macroscopic observable change in colour is from deep purple to a brown suspension, or even to colourless Mn^(2+) ion.
Potassium dichromate, K_2Cr_2O_7 is another potent oxidant, and this formed the basis of the old alcohol breath tests. The orange dichromate used to be reduced by ethyl alcohol to green Cr^(3+). When you were stopped for a breath test, if the crystals turned green you were in the poo. These days, the breathalyzers are not based on this test.
"Oxidation (i)"
H_3C-CH_2OH +H_2O rarr H_3C-CO_2H +4H^(+) + 4e^-
"Reduction (ii)"
MnO_4^(-)+4H^+ + 3e^(-) rarr MnO_2(s) +2H_2O
"Overall: "3xx(i)+4xx(ii)
3H_3C-CH_2OH +4MnO_4^(-)+4H^+ rarr 3H_3C-CO_2H +4MnO_2(s) +5H_2O
