Reduction capacity of various carboxylic acids

Chemicals needed

diluted potassium permanganate solution

sodium acetate

sodium formate GSGESUND.gif (476 Byte) Xi   R 36    S 26

oxalic acid GSGESUND.gif (476 Byte) Xn    R 21/22    S (2)-24/25

sulphuric acid 10%  GSGESUND.gif (476 Byte) Xi   R 36/38    S (1/2)-26-30-45

One can also use alkaline oxalates. Likewise formic or acetic acid, solid salts are however easy to use.

Equipment needed

3 test tubes
test tube rack
burner (preferably alcohol)

Test procedure


The diluted solutions can be discharged into the drainage.


Formic acid and oxalic acid are oxidized to carbonic acid. Acetic acid is, as is the case with almost all carboxylic acids, not readily oxidized.


DSCN0221.JPG (219629 Byte)

The acetic acid solution remains colored even after boiling, the others are decolorized.


Inspired by experiment 1696 S, "Reduktion von Kaliumpermanganat durch Oxalsäure", [2], as well as theorectical considerations.