Textbook Question
The 1H NMR spectrum of 2-propen-1-ol is shown here. Indicate the protons in the molecule that are responsible for each of the signals in the spectrum.
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15. Analytical Techniques:IR, NMR, Mass Spect
NMR Practice
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A 1H NMR spectrum has a singlet at 4.1 ppm with an integration of 2H. How many hydrogen atoms are on the neighboring carbon atom?
A
4
B
2
C
1
D
0
Verified step by step guidance1
Identify the type of signal: The problem states that there is a singlet at 4.1 ppm. In NMR spectroscopy, a singlet indicates that the hydrogen atoms giving rise to this signal are not split by any neighboring hydrogen atoms.
Understand the integration: The integration of 2H means that the signal corresponds to two equivalent hydrogen atoms.
Apply the n+1 rule: In NMR, the splitting pattern of a signal is determined by the number of neighboring hydrogen atoms using the n+1 rule, where n is the number of neighboring hydrogens. A singlet (1 peak) suggests n = 0, meaning there are no neighboring hydrogens.
Consider the chemical shift: The chemical shift at 4.1 ppm is typical for hydrogen atoms that are deshielded, possibly due to being near an electronegative atom or group, but this does not affect the number of neighboring hydrogens.
Conclude the number of neighboring hydrogens: Since the signal is a singlet, the number of hydrogen atoms on the neighboring carbon atom is 0, as there is no splitting observed.
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