# How to turn acetaldehyde into acetic acid using one of the five chemicals on the list?

It's easy to see $X$ is $\ce{H2O}$: water turns acetylene into acetaldehyde.

But what can turn acetaldehyde into acetic acid?

I checked: $\ce{NaOH}$ would turn it into sodium acetate, $\ce{CuO}$ would not react (you'd need $\ce{Cu(OH)2}$), ethanol would turn it into either an acetal or hemiacetal.

Would acetaldehyde react with formic acid to produce acetic acid? I tried to google for it, and found no mention.

Would water in the presence of a heat source somehow react with acetaldehyde? I googled and discovered that it might form hydrates, not acetic acid.

So I'm at a loss. If you consider the question too easy, you could give just a hint.

• If you Google CuO oxidation of aldehydes you do get hits – Waylander Apr 24 '17 at 13:08
• I don't think it's a stretch to think that two copper(II) reagents would both do the trick, considering one is essentially just the hydrated form of the other... – Zhe Apr 24 '17 at 13:41
• chemistry.stackexchange.com/questions/50642/… – Nilay Ghosh Apr 24 '17 at 14:25

## 1 Answer

Oxidation of aromatic aldehydes to acids by air oxidation catalysed by CuO is reported in Molecules 2008 13 948

None of the other reagents can oxidise aldehyde to acid.

• Acetaldehyde isn't aromatic. – Pritt Balagopal Apr 24 '17 at 13:45
• I know!! But given that CuO oxidises aromatic aldehydes it is not such a stretch to think it probably will oxide acetaldehyde. Plus none of the other options look even remotely right – Waylander Apr 24 '17 at 14:01
• – Nilay Ghosh Apr 24 '17 at 14:35
• Perhaps, but remember that we are supposed to solve the conceptual difficulties, not eliminate options like in a competitive examination. However I agree that $\ce{CuO}$ has a better chance of oxidizing. – Pritt Balagopal Apr 24 '17 at 16:01
• @Waylander use proper citation. Bold the year of paper. – Nilay Ghosh Apr 25 '17 at 8:05