Chem question help pls

Hi, please could I have some help on part d? I thought that ethanedioic is further oxidised to carbon dioxide and water?
Question: https://ibb.co/qLH1jmNC
Thanks!

Hi, please could I have some help on part d? I thought that ethanedioic is further oxidised to carbon dioxide and water?
Question: https://ibb.co/qLH1jmNC
Thanks!

Isn't it that methanoic can go to CO2, but ethanoic and longer can't?

It’s a mix of fumaric and maleic acid you should have at the start of step D (since H2SO4 will eliminate the hydroxyl and a neighbouring proton as water, giving you a mixture of the E- and Z-isomers of HOOC-CH=CH-COOH).
Essentially hot, concentrated acidic KMnO4 will oxidise the alkene first to give a pair of aldehydes (HOOC-CHO), which in theory should oxidise further to ethanedioic acid and then CO2 and water. In theory this should happen quite quickly as Mn^2+ ions formed in the early stages of reaction will catalyse it.
I guess they failed to give you an indication as to how concentrated the solution was and thus the mole ratio of butenedioic acids to MnO4^-, so it’s hard to say when the reaction stops.

Oh ok, so it’s just something to know? But usually ethanedioic acid will be oxidised to co2 and h2o right?

I agree - it’s a pretty dodgy question imo

Whilst this is true for the standard carboxylic acids, when you look at the dicarboxylic acids it’s ethanedioic acid only that can be oxidised.
Ethanedioic acid is actually a special case they teach about in some A level syllabi because it has an autocatalytic reaction with acidified KMnO4.

Should have gone to Specsavers.