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So I read recently that:

Alcoholic solutions of sodium hydroxide will oxidize in air, turning brown.

First is this true?

And if so what is oxidizing?

I can't think of what sodium hydroxide would oxidize to, and ethanol well wouldn't that oxidize to water and CO2!

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    $\begingroup$ Alcohol may be oxidized to aldehyde or acid. $\endgroup$ Apr 29, 2019 at 9:13
  • $\begingroup$ @KemonoChen ah true! But would that turn brown? $\endgroup$ Apr 29, 2019 at 9:54
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    $\begingroup$ In the presence of alkali (or acid, for that matter) aldehyde will turn against itself, creating all matters of ugly polycondensate products. See Aldol condensation and note that it ends up in another aldehyde, so the process can and will be repeated. $\endgroup$ Apr 29, 2019 at 9:57
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    $\begingroup$ Maybe the solution forms sodium alkoxide which is a solid that gradually turns dark in dry air due to oxidation. In moist air, it hydrolyze rapidly to sodium hydroxide. See: en.wikipedia.org/wiki/Sodium_ethoxide $\endgroup$ Apr 29, 2019 at 11:11

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[Answer based on comments from @KemonoChen, @IvanNeretin and @NilayGhosh. Thanks for your input :D]

In the presence of alkali (or acid, for that matter) aldehyde will turn against itself, creating all matters of ugly polycondensate products. See Aldol condensation and note that it ends up in another aldehyde, so the process can and will be repeated

So yes it can happen.

And is is most likely ethanol oxidation to an aldehyde, which has (aldol) condensed into an 'ugly polycondensate'

It may also be Sodium Alkoxide, which is known to turn brown.

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