Spectroscopy

1007. How many different types of carbon signals would be observed by 13C-NMR?

1 2 3


How many different types of proton signals would be observed by 1H-NMR?

1 2 3

1046.

a. Which compound absorbs at the highest field in the 1H NMR spectrum?

 

CH3Cl, CH2Cl2, CH4, CHCl3

 

b. Which of these compounds absorbs at the lowest field in the 1H NMR spectrum?

 

CH3Cl, CH2Cl2, CH4, CHCl3

 

c. Which of these brominated compounds absorbs at the lowest field in the 1H NMR spectrum?

d. Which of these compounds absorbs at the highest field in the 1H NMR spectrum?

 

CH2Cl2, CHCl3, CH3Cl, CH3I

 

1047.

a. Which compound has the C-X vibration that occurs at the highest frequency in the IR spectrum?

 

CH3CH2Br, CH3CH2Cl, CH3CH2F, CH3CH2I

 

b. Which compound has the highest wavenumber absorption in the IR spectrum?

 

 

1048. How many resonances does each compound have in the 13C spectrum at room temperature?

 

3,4,5 3,4,5

 

 

3,4,53,4,5

 

 

 

3,4,53,4,5

 

1052. Which structure corresponds to this NMR spectrum? The resonance at 4.2 ppm is a quartet and a singlet. The molecule's formula is C9H11O2N.

 

 

 

 

A. B.

C.D.

E.

 

1053. Which structure fits both the 1H and the 13C NMR spectra found below? The molecule's formula is C5H9OCl. (The three small lines in the 13C spectrum at 77 ppm are due to CDCl3.)

 

 

A. B. C.

D. E.

 

1054. Which structure corresponds to this NMR spectrum? The resonance at 3.5 ppm is due to the overlap of a quartet and a triplet. The molecule's formula is C9H11O2N.

 

 

 

 

A. B. C.D.

E.

 

1055. Which structure fits both the 1H and the 13C NMR spectra found below? The molecule's formula is C4H8Cl2. (The three small lines in the 13C spectrum at 77 ppm are due to CHCl3.)

 

A. B. C.

 

 

D.

1056. The isomers 3-heptanol and 4-heptanol are difficult to distinguish by either IR or 1H NMR. The proton-decoupled 13C NMR spectra of these compounds are shown below. Which spectrum corresponds to 3-heptanol?

A.

 

B.

1057. The isomers 1-cis, 3-cis, 5-trimethylcyclohexane and 1-cis, 3-trans, 5-trimethylcyclohexane are difficult to distinguish by either IR or 1H NMR. The proton-decoupled 13C NMR spectra of these compounds are shown below. Which spectrum corresponds to the trans isomer?

A.



B.



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