June 04, 2020, 01:41:00 AM
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Topic: Instability of methanoic acid and ethanedioic acid  (Read 12565 times)

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Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #15 on: June 20, 2012, 12:43:43 AM »
What is the functional group of an aldehyde? Compare this with the formula of formic acid.
What is the formula of Hydroxy-Methanal. ;D ;D ;D

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #16 on: June 20, 2012, 01:09:46 AM »
What is the functional group of an aldehyde? Compare this with the formula of formic acid.
What is the formula of Hydroxy-Methanal. ;D ;D ;D

Ahhhhh i seee now i get it!! Haha the 'alcohol' group of the carboxylic acid group is further oxidised to produce another carbon oxygen double bond right? And this loses the hydrogen to form carbon dioxide while the hydrogen is oxidised by the oxidising agent to produce water!


Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #17 on: June 20, 2012, 01:15:09 AM »
Something like that.

H-COOH you can write also as HO-CHO . The formic acid contains still an Aldehyde function. So it is easy to oxidise further to Hydroxy-formic acid HO-COOH, also known as carbonic acid H2CO3. This decompose to carbondioxide and water as we know.

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #18 on: June 20, 2012, 01:26:54 AM »
Something like that.

H-COOH you can write also as HO-CHO . The formic acid contains still an Aldehyde function. So it is easy to oxidise further to Hydroxy-formic acid HO-COOH, also known as carbonic acid H2CO3. This decompose to carbondioxide and water as we know.

Now that is cool... What about ethanedioic acid? Can it end up to be carbonic acid also? But there are two carbon atoms so how will it rearrange itself after further oxidation?

And why dont other organic acids have this further oxidation reaction? Why are the other organic acids more stable?

Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #19 on: June 20, 2012, 01:33:19 AM »
In oxalic acid we have HOOC-COOH.  What can you see if you look at this molecule? it jumpes directly in your eyes, I hope. :D :D


Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #20 on: June 20, 2012, 01:41:28 AM »
In oxalic acid we have HOOC-COOH.  What can you see if you look at this molecule? it jumpes directly in your eyes, I hope. :D :D
It splits up to form two molecules of carbon dioxide? :D so in this case, i can say that in the decomposition of organic acids, not all will be further oxidised to form carbonic acid first before decomposition?

Offline Hunter2

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #21 on: June 20, 2012, 01:50:32 AM »
HOOC-COOH expells one CO2 and then we have.....Bingo my friend. The rest as before.

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #22 on: June 20, 2012, 01:52:39 AM »
HOOC-COOH expells one CO2 and then we have.....Bingo my friend. The rest as before.

Cool!! Thank you so much for explaining this to me :) really appreciate it because ive never had a proper explanation by anyone for many months already since i first had this question. Finally i understand it :)

Offline AWK

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #23 on: June 20, 2012, 08:15:15 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.

During oxidation of sugar (sucrose, Saccharose) with concentrated nitric acid you can obtain the oxalic acid with good yield
AWK

Offline Darren

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Re: Instability of methanoic acid and ethanedioic acid
« Reply #24 on: June 20, 2012, 10:41:38 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.

During oxidation of sugar (sucrose, Saccharose) with concentrated nitric acid you can obtain the oxalic acid with good yield

Why doesnt the oxalic acid oxidise further to produce carbon dioxide? Why is a good yield obtained? Or does it depend on the strength of the oxidising agent? How can you determine the strength of an oxidising agent?

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