matching instruments to tasks

[sam0001]

Two pure soltuions of ethanol and ethanoic acid have lost their labels. the most appropriate instrumental analysis to use to distinguish and determine the concentrations of the organic molecules is

A GC
B HNMR
C IR SPEC
D AAS

id say C, why is the answer A?

[nerfsdacier]

Two pure soltuions of ethanol and ethanoic acid have lost their labels. the most appropriate instrumental analysis to use to distinguish and determine the concentrations of the organic molecules is

A GC
B HNMR
C IR SPEC
D AAS

id say C, why is the answer A?

Not 100% sure, but maybe cos they also want the concentration.. Can IR work out concentration as well?

[Nobby]

Not 100% sure, but maybe cos they also want the concentration.. Can IR work out concentration as well?

It can, but in VCE Chemistry I don't think it's covered.

[sam0001]

IR can determine the concentration, in much the same way as UV does.

[charmanderp]

It says the most appropriate. Since both substances are volatile and GC is highly accurate when you have a molar mass of <300, it makes it the best tool. IR Spec isn't quite so accurate for quantitative analysis, I believe. It's also very easy to distinguish between compounds using GC, as you can just run a few samples and compare retention time, and then do your calibration curve with your standard solutions, get peak area, etc.