Grabbed conquering chem exam markers' notes on the question. It's not in the syllabus because I didn't find it on the current boardofstudies version.
You got that idiot of a question from my chem '02 paper! :cross:
Question 32 – Forensic Chemistry (25 marks)
(CCHSC page 458-9) (a) (i) the alcohol functional group, –OH
For 3 marks you probably need to say that 1-propanol forms propanoic acid while glycerol forms carbon dioxide and give the half equations for both. And perhaps say that glycerol uses up much more permanganate per mole than 1-propanol does since this is a compare question.
To be on the safe side give the half equation for permanganate, if you know it. Do not try to write balanced overall equations: it's too time-consuming for the 5.4 minutes available.
This material has been deleted from the syllabus for 2003 and onwards.
(CCHSC pages 460-1)
(ii) 1-propanol reacts with permanganate to form propanoic acid. The half equations are:
CH3–CH2–CH2–OH + H2O ® CH3–CH2–COOH + 4H+ + 4e–
MnO4– + 8H+ + 5e– ® Mn2+ + 4H2O
(so 5 moles of 1-propanol react with 4 moles of permanganate or
1 mole of propanol reacts with 0.8 mole permanganate.)
Glycerol reacts with permanganate to form CO2:
HO–CH2–CHOH–CH2–OH + 3H2O ® 3CO2 +14H+ + 14e–
(so 5 moles glycerol react with 14 moles permanganate or
1 mole glycerol reacts with 2.8 moles permanganate.)
Glycerol uses much mor permanganate per mole than does 1-propanol.
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If you want the mechanism for conversion from propanol to propanioc acid, go here and look up the chromate one for comparison. I assure you that you won't find anything else on reactions of glycerol with cold dilute KMnO4 from google, only the showy one with adding
drops of glycerol to KMnO4 crystals. The grammar of that question was misleading.
http://www.usm.maine.edu/~newton/Chy251_253/Lectures/Oxidation of Alcohols/OxidationFS.html
