Redox reactions of ethanol and oxygen

[Chazef]

So there I was doing chapter 8 in the heinemann textbook (end of AOS1) when question 7 asks me to write the half-equations of the oxidation of ethanol and the reduction of oxygen. I have no idea how I was supposed to know that ethanol oxidised to CH3CHOOH and I also wasn't sure about the reduction of oxygen. Is this something I'm supposed to be able to work out or is it assumed knowledge?

Book's Question:
Blood alcohol content can also be determined by using a fuel cell. Write half equations describing the oxidation of ethanol and reduction of oxygen in an acidic electrolyte.

Book's answer:
CH3CH2OH + H2O --> CH3CHOOH + 4H+ + 4e–
O2 + 4H+ + 4e– --> 2 H2O

[rebeccab26]

So there I was doing chapter 8 in the heinemann textbook (end of AOS1) when question 7 asks me to write the half-equations of the oxidation of ethanol and the reduction of oxygen. I have no idea how I was supposed to know that ethanol oxidised to CH3CHOOH and I also wasn't sure about the reduction of oxygen. Is this something I'm supposed to be able to work out or is it assumed knowledge?

Book's Question:
Blood alcohol content can also be determined by using a fuel cell. Write half equations describing the oxidation of ethanol and reduction of oxygen in an acidic electrolyte.

Book's answer:
CH3CH2OH + H2O --> CH3CHOOH + 4H+ + 4e–
O2 + 4H+ + 4e– --> 2 H2O

Hey!
It tells you write an oxidation reaction for ethanol and reduction for oxygen.
Remember: AN OIL RIG CAT
Oxidation Is Loss of electrons, thus,  CH3CH2OH + H2O --> CH3CHOOH + 4H+ + 4e–
Reduction is gain of electrons, thus, O2 + 4H+ + 4e– --> 2 H2O
Pretty sure you can get these equations from the reduction potential table included in the textbook and data book.
Make sense?

[teletubbies_95]

 whats the reduction potential table? is the electrochemical series? ! : ) 

[rebeccab26]

whats the reduction potential table? is the electrochemical series? ! : )

yep same thing!
i just couldnt remember which term the textbook used

[Chazef]

I'm aware of the oil rig mnemonic, but it doesn't really explain why ethanoic acid ethanol loses a hydrogen and gains an oxygen. Also, the VCAA data book doesn't include ethanol in the electrochemical series

[rebeccab26]

does this make more sense?

[Chazef]

surely we're not expected to understand that level of organic chemistry for area of study 1, amarite?

[rebeccab26]

surely we're not expected to understand that level of organic chemistry for area of study 1, amarite?

naah you're not don't stress over it

[teletubbies_95]

im still confused?

so alcohol( primary ) oxidised to aldehyde ( but since its unstable) it is oxidised to carboxylic acid?

[rebeccab26]

im still confused?

so alcohol( primary ) oxidised to aldehyde ( but since its unstable) it is oxidised to carboxylic acid?

perfect

[Hancock]

The only thing you need to know about that pathway is that

Primary alcohol is oxidised to ?noic Acid.

Aldehydes are run through in Chemistry 1 at university.

[teletubbies_95]

okay! thanks guys !