Chapter Sixteen
1.
Which of the following can not be probed by an NMR spectrometer?
A)
nucleus with odd number of protons & odd number of neutrons
B)
nucleus with odd number of protons &even number of neutrons
C)
nucleus with even number of protons & odd number of neutrons
D)
nucleus with even number of protons & even number of neutrons
E)
none of these
Ans:
D
2.
How many nuclear spin states are possible for the 1H nucleus?
A)
1
B)
2
C)
4
D)
5
E)
none of these
Ans:
B
3.
Which of the following electromagnetic radiation is used in NMR spectroscopy?
A)
UV
B)
IR
C)
visible
D)
-rays
E)
radio wave
Ans:
E
4.
_______ protons experience a net magnetic field strength that is smaller than the applied
magnetic field.
A)
deshielded
B)
shielded
C)
paramagnetic
D)
diamagnetic
E)
none of these
5.
_______ protons experience a net magnetic field strength that is higher than the applied
magnetic field.
A)
deshielded
B)
shielded
C)
paramagnetic
D)
diamagnetic
E)
none of these
Ans:
A
6.
Which of the following is true about the relationship between the energy gap (E)
between the spin states for a 1H nucleus and the strength of the external magnetic field?.
A)
they are inversely proportional
B)
they are directly proportional
C)
there is no relationship
D)
the magnetic field is slightly less
E)
none of these
B
Ans:
B
7.
The strength of the magnetic field is a determining factor for the range of _______that
must be used for NMR spectrometer.
A)
temperature
B)
frequencies
C)
tesla
D)
spin states
D)
none of these
8.
Which of the following is not a common solvent used for acquiring a 1H NMR
spectrum?
A)
CDCl3
B)
CCl4
C)
CD3CN
D)
CH3OH
E)
D2O
Ans:
D
9.
Which of the following is true about the number of signals in a 1H NMR spectrum?
A)
it indicates the number of neighboring protons
B)
it indicates the electronic environment of neighboring protons
C)
it indicates the number of different kinds of protons
D)
it indicates the electronic environment of absorbing protons
E)
it indicates the number of protons in the signal
Ans:
C
Ans:
B
10.
Which of the following is true about the location of signals in a 1H NMR spectrum?
A)
it indicates the number of neighboring protons
B)
it indicates the electronic environment of neighboring protons
C)
it indicates the number of different protons
D)
it indicates the electronic environment of absorbing protons
E)
it indicates the number of protons in the signal
11.
Which of the following is true about the area under each signal in a 1H NMR spectrum?
A)
it indicates the number of neighboring protons
B)
it indicates the electronic environment of neighboring protons
C)
it indicates the number of different protons
D)
it indicates the electronic environment of absorbing protons
E)
it indicates the number of protons in the signal
Ans:
E
12.
Which of the following is true about the shape of the signal in a 1H NMR spectrum?
A)
it indicates the number of neighboring protons
B)
it indicates the electronic environment of neighboring protons
C)
it indicates the number of different protons
D)
it indicates the electronic environment of absorbing protons
E)
it indicates the number of protons in the signal
Ans:
A
Ans:
D
13.
Which of the following type of protons are chemically non equivalent?
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
A & B
E)
B & C
14.
Which of the following type of protons are chemically equivalent?
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
A & B
E)
B & C
Ans:
D
15.
Protons Ha and Hb in the following compound are _________.
HaHb
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
mesotopic
E)
none of these
Ans:
A
Ans:
C
16.
Protons Ha and Hb in the following compound are _________.
HaHb
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
mesotopic
E)
none of these
17.
Protons Ha and Hb in the following compound are _________.
Hb
Ha
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
mesotopic
E)
none of these
Ans:
C
Ans:
B
18.
Protons Ha and Hb in the following compound are _________.
Br
Ha
H
Hb
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
mesotopic
E)
none of these
19.
Protons Ha and Hb in the following compound are _________.
OH
Hb
Ha
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
mesotopic
E)
none of these
Ans:
C
Ans:
C
20.
Protons Ha and Hb in the following compound are _________.
Ha
Hb
A)
homotopic
B)
enantiotopic
C)
diastereotopic
D)
mesotopic
E)
none of these
21.
How many signals would you expect to find in the 1H NMR spectrum of
CH3OCH2CH3?
A)
1
B)
2
C)
3
D)
4
E)
5
Ans:
C
22.
How many signals would you expect to find in the 1H NMR spectrum of
CH3OCH2CH2OCH3?
A)
1
B)
2
C)
3
D)
4
E)
5
Ans:
B
Ans:
C
23.
How many signals would you expect to find in the 1H NMR spectrum of
(CH3)2CHCH2CH2CH3?
A)
1
B)
2
C)
3
D)
4
E)
5
24.
How many signals would you expect to find in the 1H NMR spectrum of
HOCH2CH2CH2CH2OH?
A)
1
B)
2
C)
3
D)
4
E)
5
Ans:
C
25.
How many signals would you expect to find in the 1H NMR spectrum of the following
compound?
A)
4
B)
5
C)
6
D)
7
E)
8
Ans:
D
Ans:
E
26.
How many signals would you expect to find in the 1H NMR spectrum of the following
compound?
O
O
A)
4
B)
5
C)
6
D)
7
E)
8
27.
How many signals would you expect to find in the 1H NMR spectrum of the following
compound?
O OH
A)
4
B)
5
C)
6
D)
7
E)
9
Ans:
D
28.
How many signals would you expect to find in the 1H NMR spectrum of the following
compound?
O
O
Ans:
4
Ans:
B
29.
How many signals would you expect to find in the 1H NMR spectrum of the following
compound?
O
Cl
O
Ans:
6
30.
How many signals would you expect to find in the 1H NMR spectrum of the following
compound?
OO
Ans:
3
31.
The 1H NMR spectrum of bromoethane shows a signal at 3.5ppm when the spectrum is
recorded using a 60-MHz spectrometer. Where do you expect to see the signal if a 300-
MHz instrument is used instead?
A)
3.5 ppm
B)
7.5 ppm
C)
6.8 ppm
D)
5.8 ppm
E)
none of these
Ans:
A
32.
______is used as a reference for recording NMR spectroscopy and is assigned a
chemical shift value of zero.
33.
Which of the indicated protons in the following compound would appear most
downfield in the 1H NMR spectrum?
I
II IV
OH
III
A)
I
B)
II
C)
III
D)
IV
Ans:
D
34.
Which of the indicated protons in the following compound would appear most
downfield in the 1H NMR spectrum?
II
IIII
IV
C CH3
C
H
C
H
F
H
HH
H
V
A)
I
B)
II
C)
III
D)
IV
E)
V
Ans:
E
35.
Which of the indicated protons in the following compound would appear most upfield in
the 1H NMR spectrum?
I III
O
O O
F
II IV
A)
I
B)
II
C)
III
D)
IV
E)
I & III
36.
Which of the following is a correct prediction of the chemical shifts for the signals in
the 1H NMR spectrum for the following compound?
III
II
HO
O
I
A)
I=3.7 ppm, II=2.7 ppm, III=1.9 ppm
B)
I=3.7 ppm, II=2.2 ppm, III=1.9 ppm
C)
I=3.9 ppm, II=2.7 ppm, III=1.9 ppm
D)
I=3.9 ppm, II=2.2 ppm, III=2.4 ppm
E)
none of these
Ans:
C
Ans:
A
37.
Which of the following is a correct prediction of the chemical shifts for the signals in
the 1H NMR spectrum for the following compound?
IV
III
I
O
O
II
A)
I=3.9 ppm, II=4.2 ppm, III=2.2 ppm, IV=3.4 ppm
B)
I=3.4 ppm, II=2.2 ppm, III=2.2 ppm, IV=3.4 ppm
C)
I=3.4 ppm, II=2.2 ppm, III=4.2 ppm, IV=3.4 ppm
D)
I=3.4 ppm, II=4.2 ppm, III=4.2 ppm, IV=3.4 ppm
E)
none of these
38.
Which of the following is a correct prediction of the chemical shifts for the signals in
the 1H NMR spectrum for the following compound?
II IV
O
O
III
I
A)
I=0.9 ppm, II=1.7 ppm, III=3.9 ppm, IV=2.4 ppm
B)
I=0.9 ppm, II=1.2 ppm, III=3.7 ppm, IV=1.9 ppm
C)
I=0.9 ppm, II=1.7 ppm, III=3.4 ppm, IV=2.4 ppm
D)
I=0.9 ppm, II=1.7 ppm, III=3.4 ppm, IV=1.9 ppm
E)
none of these
Ans:
A
Ans:
D
39.
Which of the following is a correct prediction of the chemical shifts for the signals in
the 1H NMR spectrum for the following compound?
II
IV
O
OIII
IO
A)
I=0.9 ppm, II=2.7 ppm, III=1.2 ppm, IV=0.9 ppm
B)
I=1.1 ppm, II=3.2 ppm, III=1.4 ppm, IV=0.9 ppm
C)
I=0.9 ppm, II=1.7 ppm, III=1.2 ppm, IV=1.1 ppm
D)
I=0.9 ppm, II=1.9 ppm, III=3.4 ppm, IV=0.9 ppm
E)
none of these
40.
Predict the chemical shifts for the signals in the 1H NMR spectrum for the following
compound.
O
O
O
O
II
III
IV
Ans:
B
41.
Predict the chemical shifts for the signals in the 1H NMR spectrum for the following
compound?
O
O O
42.
Aromatic protons produce signal in the range of 7-8 ppm, due to the _________effect of
electrons
A)
diamagnetic anisotropy
B)
paramagnetic anisotropy
C)
diamagnetic isotropy
D)
paramagnetic isotropy
E)
none of these
Ans:
A
43.
Which of the following protons appear most upfield in the 1H NMR spectrum?
HH
H
II III
IV
H
I
A)
I
B)
II
C)
III
D)
IV
E)
none of these
44.
A compound with molecular formula C8H14 has the following 1H NMR spectrum.
Which of the following is the correct number of protons giving rise to each signal?
A)
I-3H, II-9H, III-2H
B)
I-2H, II-9H, III-3H
C)
I-4H, II-6H, III-4H
D)
none of these
Ans:
A
0
1
2
3
4
5
6
7
8
PPM
III
II
I
45.
A compound with molecular formula C6H11N has the following 1H NMR spectrum.
Which of the following is the correct number of protons giving rise to each signal?
A)
I-6H, II-3H, III-2H
B)
I-5H, II-4H, III-2H
C)
I-6H, II-4H, III-1H
D)
none of these
0
1
2
3
4
5
6
7
8
PPM
III
II
I
Ans:
C
46.
A compound with molecular formula C8H10O has the following 1H NMR spectrum.
Which of the following is the correct number of protons giving rise to each signal?
SDBS: National Institute of Advanced Industrial Science and Technology
47.
Which of the following four compounds gives a 1H NMR spectrum consisting of only a
singlet?
A)
1,1-dichloropropane
B)
1,3-dichloropropane
C)
1,2-dichloropropane
D)
2,2-dichloropropane
E)
none of these
Ans:
D
I
II
III
IV
Ans:
I-3H, II-2H, III-3H, IV-2H
48.
How many 1H NMR signals will 2-chloro-3-methyl-2-butene exhibit?
A)
1
B)
2
C)
3
D)
4
E)
none of these
49.
Which of the following compounds will display two triplets and a singlet in the
1H NMR spectrum?
A)
CH3CH(OCH3)2
B)
CH3OCH2CH2OCH3
C)
CH3OCH2CH(OH)CH3
D)
CH3OCH2CH2CH2CH2OCH3
E)
none of these
Ans:
D
50.
Which of the following compounds will display a singlet, a triplet and a quartet in the
1H NMR spectrum?
A)
2-chloro-4-methylpentane
B)
3-chloro-2-methylpentane
C)
3-chloropentane
D)
1-chloro-2,2-dimethylbutane
E)
3-chloro-3-methylpentane
Ans:
E
Ans:
C