12.4 How many peaks?
Each hydrogen atom that has the same electron density around it shows up in the same location in an NMR spectrum. We say that these hydrogen atoms are “chemically equivalent”. In the NMR spectrum for methanol, the three methyl hydrogen atoms appear in the same location on the spectrum because they are chemically equivalent. They appear more upfield. They are more shielded because they have more electron density around them. The hydroxyl (alcohol) hydrogen atom, since it is on the oxygen atom shows up more downfield. It is deshielded. It has less electron density around the hydrogen atom because it is attached to a very electronegative oxygen atom. Because the methyl hydrogen atoms and the hydroxyl hydrogen atom are in a different chemical environment, they show up in different locations.
1. How many peaks would appear in the 1H NMR spectra for the following compounds?
