What is the oxidation product when ethanol reacts with potassium permanganate?

1 Answer
Nov 15, 2016

Answer:

#"Acetic acid,"# #H_3C-C(=O)OH#...

Explanation:

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#