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Topic: Instability of methanoic acid and ethanedioic acid  (Read 12560 times)

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Offline Darren

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Instability of methanoic acid and ethanedioic acid
« on: June 19, 2012, 08:59:52 AM »
Why do methanoic acid and ethanedioic acid decompose so easily? What makes them so unstable that they must decompose to produce carbon dioxide and water? Arent there resonance structures of the acids which can stabilise them?

Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #1 on: June 19, 2012, 10:46:27 AM »
Why do you think they are instable?

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #2 on: June 19, 2012, 10:52:33 AM »
Why do you think they are instable?


Because from my organic chemistry teachings in sch, the teachers say that whenever a qn asks you to give the products from oxidation of an organic compound, never give methanoic acid or ethanedioic acid as the final organic products because they will be oxidised to form carbon dioxide and water instead. So from this they said that those two products are unstable and will decompose very quickly.

Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #3 on: June 19, 2012, 10:58:21 AM »
First what is sch an qn.

Both acids stable itself under normal circumstances, but if an oxidising compound is present the they will easily oxidized to the carbondioxide and water. They are reducing agents.

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #4 on: June 19, 2012, 11:04:26 AM »
First what is sch an qn.

Both acids stable itself under normal circumstances, but if an oxidising compound is present the they will easily oxidized to the carbondioxide and water. They are reducing agents.

Oops so sorry. Sch is school :D and qn is question

Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #5 on: June 19, 2012, 11:05:54 AM »
Oh I see kids language. Not my mother language.

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #6 on: June 19, 2012, 11:06:09 AM »
If they are acids, shouldnt they remain as acids? What makes them oxidise to carbon dioxide and water? If you oxidise alcohols, the most they can go to will be acids. And those acids dont get oxidised further. Why the special case for these two acids?

Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #7 on: June 19, 2012, 11:09:06 AM »
What can you see if you draw the formula of formic acid? What group you can see? And what happens after oxidising. Which acid is resulting to it?
For Oxalic acid the same thing.
« Last Edit: June 19, 2012, 11:24:36 AM by Hunter2 »

Offline Borek

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #8 on: June 19, 2012, 11:40:19 AM »
sch qn i

Please read forum rules. Official language of Chemical Forums is English, not textese.
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Offline Borek

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #9 on: June 19, 2012, 11:42:16 AM »
If you oxidise alcohols, the most they can go to will be acids. And those acids dont get oxidised further.

Yes they do, it is just a matter of how harsh conditions are.
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Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #10 on: June 19, 2012, 12:46:47 PM »
But i thought you cant oxidise formic acid to anything else except to carbon dioxide? Unless there is some kind of intermediate structure to it which i havent seen before. Same goes for oxalic acid?

Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #11 on: June 19, 2012, 01:07:25 PM »
Compare Alcohol go to which compound if you oxidis smoothly and if you oxidise strong.

Compare the first product with Formic acid.

Did you dont see the forest because of to much trees?

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #12 on: June 19, 2012, 01:21:08 PM »
Compare Alcohol go to which compound if you oxidis smoothly and if you oxidise strong.

Compare the first product with Formic acid.

Did you dont see the forest because of to much trees?

Alcohols are oxidised to aldehydes then to acids. I still got get how this leads to the instability or the ease of decomposition of the two acids.

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #13 on: June 19, 2012, 01:57:30 PM »
Compare the formula of an aldehyde with the formula of formic acid. What do you can see?

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #14 on: June 19, 2012, 09:34:53 PM »
Compare the formula of an aldehyde with the formula of formic acid. What do you can see?


One more oxygen atom in the acid? The C=O double bond remains there

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