VCAA 2008

[Studyinghard]

In the vac exam question 4 part c.

http://www.vcaa.vic.edu.au/vce/studies/chemistry/exams/2008/2008chem1-web.pdf

exam link there ^^

Isn't this question a big ambiguous because the H NMR shows that there is a chemical shift at around 2.3 and when you go to your data booklet that shows that there is an ester link in the molecule.

But the molecular formula states that there is only one Oxygen in the molecule.

So like totally confused.

[happyhappyland]

Databook for hnmr is meant to be vague. dont take it too seriously

[Studyinghard]

but arent you meant to use all the information they give you ?

[stonecold]

Don't even worry about the chemical shift.  It should be the last thing you use to determine molecule structure.  First worry about the number of environments, peak height and then peak splitting if you are given high res.

[m@tty]

If there is a peak down around then automatically think carboxylic acid. (I think I remember seeing delta used to represent chemical shift...) Other than this, wait till last, as stonecold said.

[stonecold]

Yeah, matty is right.  If there is a peak at 11.5 then you know it is a carboxilic acid. 

Other than that, don't really bother with chemical shift unless you get desperate.  I doubt it will even help that much...