Consider the structures of benzaldehyde and benzyl alcohol. Benzene ring with a CH2OH attached Benzene ring with an aldehyde group attached. These two structures can be distinguished by proton NMR. The hydrogen of the aldehyde group will appear downfield between 9 and 11 ppm and there is Choose... for the alcohol. Also, the methylene hydrogens in the benzyl position of the alcohol will be the only significant Choose... peak between the two structures.

no equivalent peak, upfield between 0 and 3 ppm

Explanation:

NMR stands for nuclear magnetic resonance. It is a spectroscopic technique that is used for observing the local magnetic fields around an atomic nuclei. It is used to study the chemical, physical and biological properties of the matter.

In the context, the structures of the benzaldehyde and the benzyl alcohol are distinguished by the proton NMR. The hydrogen atom of aldehyde appears downfield between 9 and 11 ppm and also there is no equivalent peak for the alcohol.

The methylene hydrogens will only be significant upfield between the 0 and 3 ppm peak between the given structures.