Question 1

The protons marked Ha and Hb in the molecule below are ________. a and Hb in the molecule below are ________.   A)  chemically equivalent or homotopic B)  enantiotopic C)  diastereotopic D)  endotopic E)  none of the above" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   chemically equivalent or homotopic
B)   enantiotopic
C)   diastereotopic
D)   endotopic
E)   none of the aboveF) A) and D)
G) B) and E)

Question 2

Deduce the identity of the following compound from the spectral data given.
C9H10O2: 13C NMR, δ 18.06 (quartet), 45.40 (doublet), 127.32 (doublet), 127.55 (doublet), 128.61 (doublet), 139.70 (singlet) (ppm), 180.98 (singlet); IR, broad 3500-2800,

Accepted Answer

Question 3

Give one reason why 13C NMR is less sensitive than 1H NMR.

Accepted Answer

Natural isotopic abundance of ...

Question 4

Deduce the identity of the following compound from the spectral data given.
C4H8O2: 1H NMR, δ 1.23 (3H, triplet), 2.00 (3H, singlet), 4.02 (2H, quartet) (ppm); IR, 2980,

Accepted Answer

Question 5

Predict the number of signals expected (disregarding splitting) in the 1H spectrum of dibutyl ether.

Accepted Answer

Question 6

Deduce the identity of the compound whose molecular formula is C4H8O3 from the spectral data provided: IR (cm-1): 2800-3300 (broad), 2950, 1750; 13C NMR (δ): 17.7 (q), 65.4 (q), 72.3 (d), 210.8 (s) (ppm)

Accepted Answer

Question 7

Deduce the identity of the following compound from the 1H NMR data given.
C5H10O: δ 1.1 (6H, doublet), 2.2 (3H, singlet), 2.5 (1H, septet) (ppm)

Accepted Answer

Question 8

Which of the following reasons best explains why aromatic protons have a larger chemical shift than protons one carbon removed from a halogen?

Accepted Answer

A)   An aromatic ring is more electron withdrawing than a halogen.
B)   A halogen is more electron withdrawing than an aromatic ring.
C)   Electron movement induces a magnetic field opposing the external field.
D)   Electron movement induces a magnetic field reinforcing the external field.E) A) and B)
F) All of the above

Question 9

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Accepted Answer

Question 10

The protons marked Ha and Hb in the molecule below are ________. a and Hb in the molecule below are ________.   A)  chemically equivalent B)  enantiotopic C)  diastereotopic D)  endotopic E)  none of the above" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   chemically equivalent
B)   enantiotopic
C)   diastereotopic
D)   endotopic
E)   none of the aboveF) A) and B)
G) A) and D)

Question 11

What multiplicities are observed in the off-resonance decoupled 13C spectrum of 2,3-dimethyl-but-2-ene?

Accepted Answer

a singlet ...

Question 12

The energy difference between the allowed spin states for an 1H nucleus is ________ the strength of the external magnetic field in which it is placed.

Accepted Answer

A)   independent of
B)   directly proportional to
C)   inversely proportional to
D)   exponentially related to
E)   logarithmically related toF) A) and D)
G) C) and D)

Question 13

Predict the number of signals expected in the proton spin decoupled 13C spectrum of 3-hexanone, CH3CH2COCH2CH2CH3.

Accepted Answer

Question 14

Deduce the identity of the following compound from the 1H NMR data given.
C6H8O4: δ 3.9 (6H, singlet), 6.1 (2H, singlet) (ppm)

Accepted Answer

Question 15

Predict the number of signals expected, their splitting, and their relative area in the 1H NMR spectrum of 2-methylpropane (isobutane).

Accepted Answer

2 signals:...

Question 16

Predict the number of distinct quartets expected in the off-resonance decoupled  
spectrum of the compound shown below.

Accepted Answer

The answer of Predict the number of distinct quartets expected...

Question 17

Predict the number of signals expected (disregarding splitting) in the 1H spectrum of m-xylene (1,3-dimethylbenzene).

Accepted Answer

Question 18

How many peaks appear in the proton spin decoupled 13 C NMR spectrum of the compound below? 13 C NMR spectrum of the compound below?   A)  2 B)  3 C)  4 D)  5 E)  6" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   2
B)   3
C)   4
D)   5
E)   6F) B) and E)
G) A) and B)

Question 19

What compound exhibits only two signals in its 1H NMR spectrum, a triplet and a quintet?

Accepted Answer

A)   BrCH2CH2CH2Br
B)   BrCH2CH2CH2Cl
C)   (CH3) 2CHCH(CH3) 2
D)   CH3CH2CH2CH3
E)   (CH3) 2CHOCH(CH3) 2F) A) and C)
G) D) and E)

Question 20

Which compound generates positive peaks for the carbonyl in both its DEPT-90 and DEPT-135 spectra?

Accepted Answer

A)   CH3CH2CHO
B)   CH3CH2COCH3
C)   CH3CO2CH2CH3
D)   CH3CH2CONH2
E)   H2COF) B) and E)
G) None of the above

Exam 13: Nuclear Magnetic Resonance Spectroscopy

Deduce the identity of the compound whose molecular formula is C4H8O3 from the spectral data provided: IR (cm-1): 2800-3300 (broad), 2950, 1750; 13C NMR (δ): 17.7 (q), 65.4 (q), 72.3 (d), 210.8 (s) (ppm)

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How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

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Deduce the identity of the following compound from the spectral data given. C9H10O2: 13C NMR, δ 18.06 (quartet), 45.40 (doublet), 127.32 (doublet), 127.55 (doublet), 128.61 (doublet), 139.70 (singlet) (ppm), 180.98 (singlet); IR, broad 3500-2800,

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Predict the number of signals expected, their splitting, and their relative area in the 1H NMR spectrum of 2-methylpropane (isobutane).

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Which of the following reasons best explains why aromatic protons have a larger chemical shift than protons one carbon removed from a halogen?

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The protons marked Ha and Hb in the molecule below are ________.

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The energy difference between the allowed spin states for an 1H nucleus is ________ the strength of the external magnetic field in which it is placed.

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Predict the number of signals expected (disregarding splitting) in the 1H spectrum of dibutyl ether.

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What compound exhibits only two signals in its 1H NMR spectrum, a triplet and a quintet?

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How many peaks appear in the proton spin decoupled 13 C NMR spectrum of the compound below?

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Deduce the identity of the following compound from the 1H NMR data given. C5H10O: δ 1.1 (6H, doublet), 2.2 (3H, singlet), 2.5 (1H, septet) (ppm)

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The protons marked Ha and Hb in the molecule below are ________.

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Predict the number of signals expected in the proton spin decoupled 13C spectrum of 3-hexanone, CH3CH2COCH2CH2CH3.

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Predict the number of signals expected (disregarding splitting) in the 1H spectrum of m-xylene (1,3-dimethylbenzene).

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Give one reason why 13C NMR is less sensitive than 1H NMR.

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Predict the number of distinct quartets expected in the off-resonance decoupled spectrum of the compound shown below.

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Deduce the identity of the following compound from the spectral data given. C4H8O2: 1H NMR, δ 1.23 (3H, triplet), 2.00 (3H, singlet), 4.02 (2H, quartet) (ppm); IR, 2980,

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What multiplicities are observed in the off-resonance decoupled 13C spectrum of 2,3-dimethyl-but-2-ene?

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Deduce the identity of the following compound from the 1H NMR data given. C6H8O4: δ 3.9 (6H, singlet), 6.1 (2H, singlet) (ppm)

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Which compound generates positive peaks for the carbonyl in both its DEPT-90 and DEPT-135 spectra?

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Deduce the identity of the compound whose molecular formula is C₄H₈O₃ from the spectral data provided: IR (cm^-1): 2800-3300 (broad), 2950, 1750; ¹³C NMR (δ): 17.7 (q), 65.4 (q), 72.3 (d), 210.8 (s) (ppm)

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How many peaks appear in the proton spin decoupled ¹³C NMR spectrum of the compound below?

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Deduce the identity of the following compound from the spectral data given. C₉H₁₀O₂: ¹³C NMR, δ 18.06 (quartet), 45.40 (doublet), 127.32 (doublet), 127.55 (doublet), 128.61 (doublet), 139.70 (singlet) (ppm), 180.98 (singlet); IR, broad 3500-2800,

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Predict the number of signals expected, their splitting, and their relative area in the ¹H NMR spectrum of 2-methylpropane (isobutane).

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2 signals:...
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The protons marked H_a and H_b in the molecule below are ________.

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The energy difference between the allowed spin states for an ¹H nucleus is ________ the strength of the external magnetic field in which it is placed.

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Predict the number of signals expected (disregarding splitting) in the ¹H spectrum of dibutyl ether.

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What compound exhibits only two signals in its ¹H NMR spectrum, a triplet and a quintet?

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How many peaks appear in the proton spin decoupled ¹³C NMR spectrum of the compound below?

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Deduce the identity of the following compound from the ¹H NMR data given. C₅H₁₀O: δ 1.1 (6H, doublet), 2.2 (3H, singlet), 2.5 (1H, septet) (ppm)

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The protons marked H_a and H_b in the molecule below are ________.

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Predict the number of signals expected in the proton spin decoupled ¹³C spectrum of 3-hexanone, CH₃CH₂COCH₂CH₂CH₃.

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Predict the number of signals expected (disregarding splitting) in the ¹H spectrum of m-xylene (1,3-dimethylbenzene).

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Give one reason why ¹³C NMR is less sensitive than ¹H NMR.

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Natural isotopic abundance of ...
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Deduce the identity of the following compound from the spectral data given. C₄H₈O₂: ¹H NMR, δ 1.23 (3H, triplet), 2.00 (3H, singlet), 4.02 (2H, quartet) (ppm); IR, 2980,

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What multiplicities are observed in the off-resonance decoupled ¹³C spectrum of 2,3-dimethyl-but-2-ene?

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a singlet ...
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Deduce the identity of the following compound from the ¹H NMR data given. C₆H₈O₄: δ 3.9 (6H, singlet), 6.1 (2H, singlet) (ppm)

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