Question

Why might NMR not be an ideal way to determine structures in a mixture?​

Answer 1

Basically NMR is used to determine the structure of a molecule,for the identification of structural isomers,Detection of hydrogen bonding,aromaticity,to determine the purity of the compounds etc.

Even though NMR is not ideal way for determining structures in mixtures it is gaining importance for the quantitative analysis of the compounds.Equilibrium mixtures can be analysed by well separating the proton signals of the components.

In mixtures the spectra will get complex peaks of many protons .So it is very difficult to identify the compounds.The peaks may get merged and may become unable to judge.

Since the nmr spectra of structure in a mixture have many protons,they all couple and give complex peaks.Therefore nmr is not an ideal way to determine the molecular structure in mixtures