Organic Chemistry, 6e (Smith)
Spectroscopy A Mass Spectrometry
1) In electron impact mass spectrometry (EIMS), what is being detected?
A) The molecular mass of the compound
B) The molecular formula of the compound
C) The mass to charge ratio of any ionic species
D) The mass to charge ratio of any neutral species
Answer: C
Difficulty: 1 Easy
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 2. Understand
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
2) What type of feature will be observed in the EI mass spectrum of chlorobenzene?
A) An absorption at 3100 cm–1
B) A signal at 113
C) A signal at 112 and a signal at 114 in a ratio of 3:1
D) A signal at 112 and a signal at 114 in a ratio of 1:1
Answer: C
Difficulty: 1 Easy
Section: A.02
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
3) You observe a compound that exhibits a mass spectrum with peak at 160 and a peak at
162, both of equal intensity. This compound contains
A) two chlorine atoms.
B) one iodine atom.
C) one bromine atom.
D) two bromine atoms.
Answer: C
Difficulty: 1 Easy
Section: A.02
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
,4) A compound X has a molecular ion peak in its mass spectrum at m/z 136. What
information does this tell us about X?
A) X has a molecular mass of 136.
B) The molecular formula for X is C8H8O2.
C) The empirical formula for X is C4H4O.
D) Both A (X has a molecular mass of 136) and B (The molecular formula for X is
C8H8O2) are true.
E) Statements (X has a molecular mass of 136), (The molecular formula for X is
C8H8O2), and (The empirical formula for X is C4H4O) are all true.
Answer: A
Difficulty: 2 Medium
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
5) What type of signal(s) would you observe in the mass and (or) infrared spectrum of the
following compound?
A) A signal at 95 amu
B) A signal at 94 amu
C) Two signals at 95 and 94 amu
D) A signal at 106 amu
Answer: A
Difficulty: 2 Medium
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
,6) In a typical mass spectrum, a smaller signal is observed at a mass 1 amu higher than
the molecular ion peak. Why?
A) Due to small impurities in the sample
B) Machine error
C) Because a small percentage of the compound will have a carbon that is the isotope 13C
instead of 12C
D) Because of fragmentation
Answer: C
Difficulty: 1 Easy
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
7) Which of the following statements about the base peak of a mass spectrum is always
true?
A) The base peak corresponds to the molecular ion.
B) The base peak corresponds to the most abundant ion.
C) The base peak corresponds to the lowest m/z.
D) None of these.
Answer: B
Difficulty: 1 Easy
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
8) What would be the molecular formula of rose oxide which contains C, H, and O and
has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z =154?
A) C10H18O
B) C9H14O2
C) C10H2O2
D) C8H10O3
Answer: A
Difficulty: 2 Medium
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
, 9) Which of the following alkanes gives a significant fragment peak at m/z = 57?
A) I
B) II
C) III
D) IV
Answer: C
Difficulty: 2 Medium
Section: A.03
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
10) 2,2-dimethylbutane gives a significant fragment peak at m/z = 57. Which of the
following is the most probable structure of the fragment ion?
A) I
B) II
C) III
D) IV
Answer: D
Difficulty: 2 Medium
Section: A.03
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Spectroscopy A Mass Spectrometry
1) In electron impact mass spectrometry (EIMS), what is being detected?
A) The molecular mass of the compound
B) The molecular formula of the compound
C) The mass to charge ratio of any ionic species
D) The mass to charge ratio of any neutral species
Answer: C
Difficulty: 1 Easy
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 2. Understand
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
2) What type of feature will be observed in the EI mass spectrum of chlorobenzene?
A) An absorption at 3100 cm–1
B) A signal at 113
C) A signal at 112 and a signal at 114 in a ratio of 3:1
D) A signal at 112 and a signal at 114 in a ratio of 1:1
Answer: C
Difficulty: 1 Easy
Section: A.02
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
3) You observe a compound that exhibits a mass spectrum with peak at 160 and a peak at
162, both of equal intensity. This compound contains
A) two chlorine atoms.
B) one iodine atom.
C) one bromine atom.
D) two bromine atoms.
Answer: C
Difficulty: 1 Easy
Section: A.02
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
,4) A compound X has a molecular ion peak in its mass spectrum at m/z 136. What
information does this tell us about X?
A) X has a molecular mass of 136.
B) The molecular formula for X is C8H8O2.
C) The empirical formula for X is C4H4O.
D) Both A (X has a molecular mass of 136) and B (The molecular formula for X is
C8H8O2) are true.
E) Statements (X has a molecular mass of 136), (The molecular formula for X is
C8H8O2), and (The empirical formula for X is C4H4O) are all true.
Answer: A
Difficulty: 2 Medium
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
5) What type of signal(s) would you observe in the mass and (or) infrared spectrum of the
following compound?
A) A signal at 95 amu
B) A signal at 94 amu
C) Two signals at 95 and 94 amu
D) A signal at 106 amu
Answer: A
Difficulty: 2 Medium
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
,6) In a typical mass spectrum, a smaller signal is observed at a mass 1 amu higher than
the molecular ion peak. Why?
A) Due to small impurities in the sample
B) Machine error
C) Because a small percentage of the compound will have a carbon that is the isotope 13C
instead of 12C
D) Because of fragmentation
Answer: C
Difficulty: 1 Easy
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
7) Which of the following statements about the base peak of a mass spectrum is always
true?
A) The base peak corresponds to the molecular ion.
B) The base peak corresponds to the most abundant ion.
C) The base peak corresponds to the lowest m/z.
D) None of these.
Answer: B
Difficulty: 1 Easy
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
8) What would be the molecular formula of rose oxide which contains C, H, and O and
has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z =154?
A) C10H18O
B) C9H14O2
C) C10H2O2
D) C8H10O3
Answer: A
Difficulty: 2 Medium
Section: A.01
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
Accessibility: Keyboard Navigation
, 9) Which of the following alkanes gives a significant fragment peak at m/z = 57?
A) I
B) II
C) III
D) IV
Answer: C
Difficulty: 2 Medium
Section: A.03
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
10) 2,2-dimethylbutane gives a significant fragment peak at m/z = 57. Which of the
following is the most probable structure of the fragment ion?
A) I
B) II
C) III
D) IV
Answer: D
Difficulty: 2 Medium
Section: A.03
Topic: Analytical/Spectroscopy
Bloom's: 3. Apply
Chapter: Spectroscopy A
