91Ó°ÊÓ

The chemical shift in ${}^{\mathbf{1}}\mathbf{H}$NMR spectroscopy denoted as role="math" localid="1652430408976" $\mathbf{δ}$tells about the environment around the atomic nuclei. The $\mathbf{δ}$scale comprises a value in the range of 0-10 ppm. A high chemical shift value indicates the proton is deshielded and a low chemical shift value shows the proton is shielded.

Each of the NMR spectra possesses signals between 7 and 8 ppm (integrating to five hydrogens).This indicates that the compound has a benzene ring with one substituent.

There is an additional signal that is a singlet. The singlet in each spectrum is due to the methyl group. The methyl group is at a higher frequency on the second spectrum. This is the spectrum of the compound on the right, as the methyl group is near to an electron-withdrawing oxygen. The compound on the left is hydrolyzed more rapidly as its OR group is a weaker base. ( The ${\mathrm{pK}}_{\mathrm{a}}$of phenol is approximately equal to 10 and that of methanol is approximately equal to 16).

Different esters