Chapter Fifteen
1.
Which of the following is not true about electromagnetic radiation?
A)
frequency is directly proportional to wavelength
B)
frequency is directly proportional to energy
C)
frequency is inversely proportional to wavelength
D)
wavelength is inversely proportional to energy
E)
none of these
Ans:
A
2.
Which of the following electromagnetic radiation has the highest energy?
A)
UV
B)
X-ray
C)
IR
D)
microwave
E)
visible
3.
Which of the following electromagnetic radiation has the longest wavelength?
A)
UV
B)
X-ray
C)
IR
D)
microwave
E)
visible
Ans:
D
4.
Which of the following electromagnetic radiation has the highest frequency?
A)
UV
B)
X-ray
C)
IR
D)
microwave
E)
visible
5.
Arrange the following electromagnetic radiation in decreasing (highest to lowest) order
of frequency.
IR UV
I III IV V
microwave -rays visible
A)
V>III>IV>II>I
B)
II>V>III>IV>I
C)
I>IV>III>V>II
D)
V>II>IV>III>I
E)
II>IV>V>III>I
Ans:
B
6.
Which of the following information is primarily obtained from infrared spectroscopy?
A)
arrangement of carbon and hydrogen atoms in a compound
B)
molecular weight of a compound
C)
conjugated system present in a compound
D)
functional groups present in a compound
E)
all of these
Ans:
D
Ans:
B
7.
Absorption of _______radiation results in vibrational excitation of the bonds in a
compound.
A)
UV
B)
Microwave
C)
IR
D)
Visible
E)
x-ray
8.
Which of the following vibrations are observed in IR spectroscopy?
A)
stetching
B)
rotational
C)
bending
D)
A & B
E)
A & C
Ans:
E
9.
Which of the following is currently used to indicate the location of a signal on an IR
spectrum?
A)
wavelength
B)
wavenumber
C)
frequency
D)
A & B
E)
all of these
Ans:
B
10.
Which of the following are units for wavenumber in IR spectroscopy?
A)
cm—1
B)
cm
C)
J.s—1
D)
mm
E)
none of these
Ans:
C
11.
Which of the following corresponds to the functional group region on an IR spectrum?
A)
1500-4000cm—1
B)
400-4000cm—1
C)
400-1500cm—1
D)
1500-2500cm—1
E)
none of these
Ans:
A
12.
Which of the following corresponds to the fingerprint region on an IR spectrum?
A)
1500-4000cm—1
B)
400-4000cm—1
C)
400-1500cm—1
D)
1500-2500cm—1
E)
none of these
Ans:
C
13.
Which of the following statement(s) is(are) true about the frequency of a stretching
vibration according to Hook’s law?
A)
it is directly proportional to strength of the bond & the reduced mass
B)
it is inversely proportional to strength of the bond & the reduced mass
C)
it is directly proportional to strength of the bond
D)
it is inversely proportional to the reduced mass
E)
C & D
Ans:
E
14.
Rank the indicated bonds in decreasing (highest to lowest) order of wavenumber.
II
III
H
HH
I
A)
III>II>I
B)
I>II>III
C)
II>I>III
D)
III>I>II
E)
none of these
15.
Rank the indicated bonds in decreasing (highest to lowest) order of wavenumber.
II
III
O
H
H
N
H
IH
A)
III>II>I
B)
I>II>III
C)
II>I>III
D)
III>I>II
E)
none of these
Ans:
D
Ans:
B
16.
Rank the indicated bonds in decreasing (highest to lowest) order of wavenumber.
II III
N
H
I
O
A)
III>II>I
B)
I>II>III
C)
II>I>III
D)
III>I>II
E)
none of these
17.
Which one of the following compounds will have the lowest wavenumber for carbonyl
absorption?
OOOOO
III III IV V
A)
I
B)
II
C)
III
D)
IV
E)
V
Ans:
D
Ans:
D
18.
Which one of the following compounds will have the lowest wavenumber for carbonyl
absorption?
III III IV
OOO NH2O
V
O
O
A)
I
B)
II
C)
III
D)
IV
E)
V
19.
Which one of the following compounds will have the highest wavenumber for C=C
absorption?
III III IV V
A)
I
B)
II
C)
III
D)
IV
E)
V
Ans:
C
Ans:
C
20.
Which of the following compounds will have the highest wavenumber for carbonyl
absorption?
O
O
O
O
O
O
III III
A)
I
B)
II
C)
III
D)
II & III
21.
Arrange the indicated bonds in decreasing (highest to lowest) order of wavenumber.
I
II
III
IV
O
V
O
O
C
N
H
A)
I>V>II>IV>III
B)
IV>II>I>V>III
C)
II>I>V>III>IV
D)
IV>I>V>II>III
E)
IV>II>V>I>III
Ans:
E
22.
Which of the following statement(s) is(are) true for an IR-active bond?
A)
the bond must be symmetrical
B)
it must change bond length
C)
it must change bond angle
D)
it must change bond dipole
E)
all of these
Ans:
D
Ans:
C
23.
Which of the following bonds is IR inactive?
IV
III
II
CH3CH2C C H
I
CH3CH2C C CH2CH3
A)
I
B)
II
C)
III
D)
I & IV
E)
I & III
24.
Which of the following bonds would produce the weakest absorption?
A)
C=C
B)
O—H
C)
C=O
D)
sp3C—H
E)
A & D
Ans:
A
25.
Which of the following bonds would produce the strongest absorption?
A)
C=N
B)
CC
C)
C=O
D)
sp2C—H
E)
C—O
Ans:
C
Ans:
E
26.
3-hexyne does not show absorption in the range of 2000-2200 cm—1, whereas 1-hexyne
does. Which of the following explains the reason for this absence of absorption for 3-
hexyne?
A)
it is a symmetrical compound
B)
there is no change in bond dipole
C)
there is no bond dipole
D)
it is an unsymmetrical compound
E)
A, B & C
27.
Which of the following alkene groups will produce the strongest signal?
FCl Br
III III IV
A)
I
B)
II
C)
III
D)
IV
Ans:
A
28.
Diluted alcohols show a _____absorption around 3600cm-1, due to _____.
A)
sharp, hydrogen bonding
B)
broad, hydrogen bonding
C)
sharp, absence of hydrogen bonding
D)
broad, absence of hydrogen bonding
Ans:
C
Ans:
E
29.
Concentrated alcohols show a _____absorption in the region of 3200-3600cm-1, due to
_____.
A)
sharp, hydrogen bonding
B)
broad, hydrogen bonding
C)
sharp, polarity
D)
broad, polarity
30.
Carboxylic acids show a very broad absorption for the OH compared to alcohols,
because they can form a ______.
A)
dimer
B)
polymer
C)
trimer
D)
tetramer
Ans:
A
31.
Primary amines show two medium absorption bands around 3400 cm-1, due to _______.
A)
symmetric stretching
B)
asymmetric stretching
C)
both symmetric and asymmetric stretching
D)
hydrogen bonding
Ans:
C
Ans:
B
32.
How can you distinguish between cyclohexanol and cyclohexanecarboxylic acid using
IR spectroscopy?
OH
OH
O
Cyclohexanecarboxylic acid
Cyclohexanol
33.
Which of the following compounds will show a broad absorption around 3300 cm-1 and
at 1650 cm-1?
OH OOOH
III III IV
O
OH
V
A)
I
B)
II
C)
III
D)
IV
E)
V
Ans:
D
and it will also show absorption for carbonyl group.
34.
Which of the following compounds will show a sharp absorption at 3300 cm-1 and at
2150 cm-1?
III III IV
C
N
A)
I
B)
II
C)
III
D)
IV
E)
none of these
35.
Which of the following compounds will show two absorptions at 2600 cm-1 and at
2700 cm-1 along with the carbonyl absorption?
III III IV
O
O
O
NH2
O
H
O
A)
I
B)
II
C)
III
D)
IV
E)
none of these
Ans:
D
36.
Which of the following compounds will show absorption at 2250 cm-1?
III III IV
NH2N
H
N
C
N
A)
I
B)
II
C)
III
D)
IV
E)
none of these
Ans:
A
37.
Which of the following compounds will have the lowest wavenumber for carbonyl
absorption?
O Cl O H O NH2O OH O O
III III IV V
A)
I
B)
II
C)
III
D)
IV
E)
V
Ans:
C
38.
Which of the following is true about the IR spectrum of the following compound?
Cl
O
A)
absorptions at 1720 cm-1 & 2150 cm-1
B)
absorptions at 1800 cm-1 & 2150 cm-1
C)
absorptions at 1720 cm-1 & 2250 cm-1
D)
absorptions at 1800 cm-1 & 2250 cm-1
E)
absorptions at 1650 cm-1 & 2150 cm-1
Ans:
B
39.
Which of the following compounds will show absorptions at 1640 cm-1, 2950 cm-1 and
3050 cm-1 on the IR spectrum?
O
O OH
III III IV V
A)
I
B)
II
C)
III
D)
IV
E)
V
40.
A compound with molecular formula C6H10O, shows absorptions at 1720 cm-1 and at
2980 cm-1 on the IR spectrum. Propose a possible structure for this compound.
41.
A compound with molecular formula C3H9N, shows absorptions at 3400 cm-1 (two),
2980 cm-1 and at 1100 cm-1 on the IR spectrum. Propose a possible structure for this
compound.
Ans:
Ans:
C
42.
A compound with molecular formula C4H8O2, shows absorptions at 2200-3600 cm-1
(broad), 1720 cm-1 and at 1200 cm-1 on the IR spectrum. Propose a possible structure for
this compound.
43.
Which of the following compounds will have highest wavenumber for carbonyl
absorption?
O
O
O
O
O
O
IIII
II
O
O
IV
A)
I
B)
II
C)
III
D)
IV
B
44.
Which of the following compounds will have two absorptions at 1820 cm-1 and
1740cm-1?
IIIIII IV
O
O O
O
O
OH
O
NH2
O
Cl
O
V
A)
I
B)
II
C)
III
D)
IV
E)
V
D
45.
Which one of the following compounds is consistent with the following IR spectrum?
SDBS: National Institute of Advanced Industrial Science and Technology
O
OH
III III IV
O OH
OH
OH
O H
OH
V
A)
I
B)
II
C)
III
D)
IV
E)
V
D
46.
Which one of the following compounds is consistent with the following IR spectrum?
SDBS: National Institute of Advanced Industrial Science and Technology
O
NH2
III III IV
N
H
N
O
NH2
N
O
OH HN
V
A)
I
B)
II
C)
III
D)
IV
E)
V
B
47.
Which one of the following compounds is consistent with the following IR spectrum?
SDBS: National Institute of Advanced Industrial Science and Technology
III III IV
OH
C
OH
N
OH
HO C
O
N
A)
I
B)
II
C)
III
D)
IV
E)
V
A
48.
Which one of the following compounds is consistent with the following IR spectrum?
SDBS: National Institute of Advanced Industrial Science and Technology
H
O
O
O
OH
III III IV
H
O
V
A)
I
B)
II
C)
III
D)
IV
E)
V