Question 1

Which of the following statements about 13C NMR is not true?

Accepted Answer

A)  "In 13C proton-decoupled NMR spectra,all peaks are singlets."
B)  "13C NMR spectra display peaks for only carbons that bear hydrogen atoms."
C)  "13C NMR chemical shifts occur over a greater range than 1H NMR chemical shifts."
D)  "13C NMR easily differentiates between the different hybridized carbons (sp3,sp2,and sp hybridized carbons) ."E) B) and D)
F) C) and D) B

Question 2

What effect does increasing the operating frequency of a 1H NMR spectrum have on the value of chemical shift in Δ?

Accepted Answer

A)  Chemical shift in Δ will also increase.
B)  Chemical shift in Δ will decrease.
C)  Chemical shift in Δ will remain the same.
D)  It is not possible to predict the change in chemical shift in Δ.E) All of the above
F) None of the above

Question 3

Which of the labeled protons would absorb furthest downfield in a 1H NMR spectrum? 1H NMR spectrum?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) C) and D)

Question 4

How many different kinds of protons are present in each of the following compounds?

Accepted Answer

A)  I = 2; II = 3; III = 4
B)  I = 2; II = 3; III = 3
C)  I = 3; II = 3; III = 3
D)  I = 3; II = 3; III = 4E) All of the above
F) None of the above

Question 5

An unknown compound has the formula of C9H12.The following 1H NMR peaks were observed: Doublet at Δ 1.22
Septet at Δ 2.83
Multiplet at Δ 7.09
From the data above,pick the compound below that fits the spectra data. 9H12.The following 1H NMR peaks were observed: Doublet at Δ 1.22 Septet at Δ 2.83 Multiplet at Δ 7.09 From the data above,pick the compound below that fits the spectra data.   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) A) and D)

Question 6

An unknown compound A has the molecular formula C7H14O2.Compound A absorbs strongly in the IR at 1700 cm-1.The 1H NMR spectral data for compound A are given below.What is the structure of compound A? 7H14O2.Compound A absorbs strongly in the IR at 1700 cm-1.The 1H NMR spectral data for compound A are given below.What is the structure of compound A?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) All of the above
F) A) and B) C

Question 7

How many peaks would be observed for each of the circled protons in the compounds below?

Accepted Answer

A)  I = 8; II = 4; III = 3; IV = 3
B)  I = 7; II = 4; III = 3; IV = 4
C)  I = 7; II = 3; III = 3; IV = 3
D)  I = 7; II = 4; III = 2; IV = 4E) A) and D)
F) A) and C)

Question 8

How many different kinds of protons are present in the following molecule?

Accepted Answer

A)  2
B)  3
C)  4
D)  5E) C) and D)
F) None of the above

Question 9

Which of the indicated protons would absorb furthest downfield in a 1H NMR spectrum? 1H NMR spectrum?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) B) and C)
F) None of the above

Question 10

How many different kinds of protons are present in each of the following compounds?

Accepted Answer

A)  I = 6; II = 5; III = 3
B)  I = 7; II = 5; III = 3
C)  I = 7; II = 6; III = 3
D)  I = 6; II = 6; III = 3E) All of the above
F) A) and D)

Question 11

Which of the following compounds does not show only one signal in its 1H NMR spectrum? 1H NMR spectrum?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) None of the above
F) B) and D)

Question 12

How many different kinds of protons are present in each of the following compounds?

Accepted Answer

A)  a: 5; b: 6
B)  a: 5; b: 5
C)  a: 4; b: 6
D)  a: 4; b: 5E) A) and D)
F) B) and C)

Question 13

How many peaks would be observed for each of the circled protons in the compounds below?

Accepted Answer

A)  I = 2; II = 6; III = 1
B)  I = 3; II = 5; III = 2
C)  I = 1; II = 5; III = 1
D)  I = 2; II = 6; III = 2E) None of the above
F) A) and B) A

Question 14

What effect does increasing the operating frequency of a 1H NMR spectrum have on the frequency of an absorption in Hz?

Accepted Answer

A)  Frequency of an absorption in Hz will also increase.
B)  Frequency of an absorption in Hz will decrease.
C)  Frequency of an absorption in Hz will remain the same.
D)  It is not possible to predict the change in frequency of an absorption in Hz.E) A) and B)
F) A) and D)

Question 15

An unknown compound X has the molecular formula C10H11O2Br.Compound X shows a strong absorption in its IR spectrum at 1700 cm-1.The 1H NMR spectral data for compound X is given below.What is the structure of compound X? 10H11O2Br.Compound X shows a strong absorption in its IR spectrum at 1700 cm-1.The 1H NMR spectral data for compound X is given below.What is the structure of compound X?   A) Only I B) Only II C) Only III D) I or II" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  Only I
B)  Only II
C)  Only III
D)  I or IIE) B) and C)
F) A) and B)

Question 16

Which of the following spectroscopy methods does not involve the interaction of organic molecules with electromagnetic radiation?

Accepted Answer

A)  Nuclear magnetic resonance
B)  Infrared spectroscopy
C)  Mass spectrometry
D)  Ultraviolet spectroscopyE) A) and D)
F) B) and D)

Question 17

Which of the following statements is true about electromagnetic radiation?

Accepted Answer

A)  All molecules absorb electromagnetic radiation at some frequency.
B)  Frequency is directly proportional to wavelength.
C)  NMR uses the microwave region of the electromagnetic spectrum.
D)  The radio frequency region of the electromagnetic spectrum has the largest energy per photon.
E)  Energy is inversely proportional to frequency.F) A) and E)
G) A) and B)

Question 18

An unknown compound A has the molecular formula C12H16O.Compound A absorbs strongly in the IR at 1700 cm-1.The NMR spectral data for compound A are given below.What is the structure of compound A? 12H16O.Compound A absorbs strongly in the IR at 1700 cm-1.The NMR spectral data for compound A are given below.What is the structure of compound A?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) B) and D)

Question 19

Which of the labeled protons absorbs furthest upfield in the 1H NMR spectrum? 1H NMR spectrum?   A) Ha B) Hb C) Hc D) Hd" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  Ha
B)  Hb
C)  Hc
D)  HdE) B) and D)
F) A) and D)

Question 20

How many peaks would be observed for each of the circled protons in the compounds below?

Accepted Answer

A)  I = 1; II = 4; III = 7
B)  I = 3; II = 3; III = 7
C)  I = 2; II = 4; III = 7
D)  I = 2; II = 4; III = 6E) A) and D)
F) A) and C)

Exam 32: Spectroscopy C: Nuclear Magnetic Resonance Spectroscopy

Which of the following statements about 13C NMR is not true?

Correct AnswerverifiedB

What effect does increasing the operating frequency of a 1H NMR spectrum have on the value of chemical shift in Δ?

Correct AnswerverifiedShow Answer

Which of the labeled protons would absorb furthest downfield in a 1H NMR spectrum?

Correct AnswerverifiedShow Answer

How many different kinds of protons are present in each of the following compounds?

Correct AnswerverifiedShow Answer

An unknown compound has the formula of C9H12.The following 1H NMR peaks were observed: Doublet at Δ 1.22 Septet at Δ 2.83 Multiplet at Δ 7.09 From the data above,pick the compound below that fits the spectra data.

Correct AnswerverifiedShow Answer

An unknown compound A has the molecular formula C7H14O2.Compound A absorbs strongly in the IR at 1700 cm-1.The 1H NMR spectral data for compound A are given below.What is the structure of compound A?

Correct AnswerverifiedC

How many peaks would be observed for each of the circled protons in the compounds below?

Correct AnswerverifiedShow Answer

How many different kinds of protons are present in the following molecule?

Correct AnswerverifiedShow Answer

Which of the indicated protons would absorb furthest downfield in a 1H NMR spectrum?

Correct AnswerverifiedShow Answer

How many different kinds of protons are present in each of the following compounds?

Correct AnswerverifiedShow Answer

Which of the following compounds does not show only one signal in its 1H NMR spectrum?

Correct AnswerverifiedShow Answer

How many different kinds of protons are present in each of the following compounds?

Correct AnswerverifiedShow Answer

How many peaks would be observed for each of the circled protons in the compounds below?

Correct AnswerverifiedA

What effect does increasing the operating frequency of a 1H NMR spectrum have on the frequency of an absorption in Hz?

Correct AnswerverifiedShow Answer

An unknown compound X has the molecular formula C10H11O2Br.Compound X shows a strong absorption in its IR spectrum at 1700 cm-1.The 1H NMR spectral data for compound X is given below.What is the structure of compound X?

Correct AnswerverifiedShow Answer

Which of the following spectroscopy methods does not involve the interaction of organic molecules with electromagnetic radiation?

Correct AnswerverifiedShow Answer

Which of the following statements is true about electromagnetic radiation?

Correct AnswerverifiedShow Answer

An unknown compound A has the molecular formula C12H16O.Compound A absorbs strongly in the IR at 1700 cm-1.The NMR spectral data for compound A are given below.What is the structure of compound A?

Correct AnswerverifiedShow Answer

Which of the labeled protons absorbs furthest upfield in the 1H NMR spectrum?

Correct AnswerverifiedShow Answer

How many peaks would be observed for each of the circled protons in the compounds below?

Correct AnswerverifiedShow Answer

Which of the following statements about ¹³C NMR is not true?

Correct Answer
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B

What effect does increasing the operating frequency of a ¹H NMR spectrum have on the value of chemical shift in Δ?

Correct Answer
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Which of the labeled protons would absorb furthest downfield in a ¹H NMR spectrum?

Correct Answer
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An unknown compound has the formula of C₉H₁₂.The following ¹H NMR peaks were observed: Doublet at Δ 1.22 Septet at Δ 2.83 Multiplet at Δ 7.09 From the data above,pick the compound below that fits the spectra data.

Correct Answer
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An unknown compound A has the molecular formula C₇H₁₄O₂.Compound A absorbs strongly in the IR at 1700 cm^-1.The ¹H NMR spectral data for compound A are given below.What is the structure of compound A?

Correct Answer
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C

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Which of the indicated protons would absorb furthest downfield in a ¹H NMR spectrum?

Correct Answer
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Correct Answer
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Which of the following compounds does not show only one signal in its ¹H NMR spectrum?

Correct Answer
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A

What effect does increasing the operating frequency of a ¹H NMR spectrum have on the frequency of an absorption in Hz?

Correct Answer
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An unknown compound X has the molecular formula C₁₀H₁₁O₂Br.Compound X shows a strong absorption in its IR spectrum at 1700 cm^-1.The ¹H NMR spectral data for compound X is given below.What is the structure of compound X?

Correct Answer
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An unknown compound A has the molecular formula C₁₂H₁₆O.Compound A absorbs strongly in the IR at 1700 cm^-1.The NMR spectral data for compound A are given below.What is the structure of compound A?

Correct Answer
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Which of the labeled protons absorbs furthest upfield in the ¹H NMR spectrum?

Correct Answer
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Correct Answer
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