13C NMR: General Features

13C NMR: General Features Additional Practice Problems

For the following compound how many different signals would you see in the carbon NMR? (Assume that you can see them all.)

A) 4

B) 5

C) 6

D) 7

E) 8

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For the following compound how many different signals would you see in the carbon NMR? (Assume that you can see them all.)

A) 1

B) 2

C) 3

D) 4

E) 5

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In 13C NMR spectroscopy, the signal due to this type of carbon occurs furthest downfield.

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How many signals would you expect to find in each range of the 13C-NMR spectrum of the following compounds? Enter a number in each box. 

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Which line in the following spectrum would indicate the presence of a carbonyl group?

a 5

b 2

c 1

d 4

e 3

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How many peaks (signals) would you expect in the broadband-decoupled  13C NMR spectrum of each of the following compounds?

Example: You would see 4 peaks (signals) in 2-butanone, CH 3COCH2CH3.

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Which carbon atom is most deshielded in the following molecule?

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Which isn't true about  13C NMR spectroscopy?

a. Each distinct carbon produces a single peak  13C  NMR spectrum.

b. Splitting of signals into multiple peaks is not observed in routine  13C  NMR spectra.

c. Decreased electron density around an atom shields the atom from the magnetic field

d. Larger mass of samples is usually required.

e. 13C  spectra are usually less complex and easier to interpret than 1H NMR

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How many peaks (signals) would you expect in the broadband- decoupled  13C NMR spectrum of each of the following compounds?

Example: You should see 4 peaks (singles) in 2-butanone, CH 3COCH2CH3.

 

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Circle the most deshielded carbon in the 13C NMR spectrum of the compound shown below.

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Which isn’t true about 13C NMR spectroscopy?

 

a) Each distinct carbon produces a single peak in 13C NMR spectrum.

b) Splitting of signals into multiple peaks is not observed in routine 13C NMR spectra.

c) Decreased electron density around an atom shields the atom from the magnetic field.

d) Larger mass of samples is usually required.

e) 13C spectra are usually less complex and easier to interpret than 1H NMR.

Watch Solution