Determining the Expected Number of Signals in the 1H NMR Spectrum of a Compound: Analyzing a Compound with a Methyl Group (CH3) Attached to a Benzene Ring

How many signals would you expect in the 1H NMR spectrum of the compound shown

To determine the number of signals you would expect in the 1H NMR spectrum of a compound, you need to consider the different types of hydrogen atoms in the molecule

To determine the number of signals you would expect in the 1H NMR spectrum of a compound, you need to consider the different types of hydrogen atoms in the molecule.

In the image you provided, we see a compound with a single methyl group (CH3) attached to a benzene ring. Let’s analyze each part separately:

1. Methyl Group (CH3):
The methyl group consists of three hydrogen atoms bonded to a single carbon atom. In general, hydrogen atoms that are bonded to the same carbon atom are chemically equivalent and will give rise to a single NMR signal. Therefore, we would expect the methyl group to contribute a single signal.

2. Benzene Ring:
Benzene is a planar, cyclic aromatic compound consisting of six carbon atoms and six hydrogen atoms. In an NMR spectrum, hydrogen atoms attached to aromatic rings typically exhibit a phenomenon called chemical shift equivalence. This means that all six hydrogen atoms in the benzene ring will have the same chemical environment and, therefore, will give rise to a single NMR signal.

Based on the analysis above, we would expect the compound to exhibit two signals in its 1H NMR spectrum: one signal corresponding to the three hydrogen atoms in the methyl group, and another signal corresponding to the six hydrogen atoms in the benzene ring.

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