Infrared / NMR Spectroscopy
Questions
Question 1
Is the following IR of cis or trans 2pentene?
A) cis
B) trans
Answer
Is the following IR of cis or trans 2pentene? B) trans 2-pentene
Question 2
C 7H 6O
Identify the compound from the IR above.
A) benzyl alcohol
B) 1,4,6-heptatrien-3-one
C) 2,4,6-heptatrienaldehyde
D) benzaldehyde
Answer
D) Benzaldehyde
wavenumber (cm–1)
2810 and 2730
745 and 690
1700
assignment
an aldehyde
mono subs benzene
carbonyl
Question 3
C10H12O
Identify the compound from the IR above.
A) 4-phenylbutanaldehyde
B) phenylpropyl ketone
C) meta-isopropylbenzaldehyde
D) 1-phenyl-2-butanone
Answer
D) 1-phenyl-2-butanone
wavenumber (cm–1)
>3000
<3000
740 and 700
1720
assignment
sp2 CH
sp3 CH
Mono subs benzene ring
non-conj ketone carbonyl
Question 4
C3H4O
Identify the compound from the IR above.
A) cyclopropanone
B) propynol
C) 2-cyclopropenol
D) 1,2-propadienol
Answer
B) propynol
wavenumber (cm–1)
3300
2950
2100
assignment
OH group
sp3 CH
alkyne
Question 5
C3H7NO
Identify the compound from the IR above.
A) N-methylacetamide
B) N,N-dimethylformamide
C) 3-aminopropanal
D) N-methylamino-ethanal
Answer
A) N-methylacetamide
wavenumber (cm–1)
3300
1660
assignment
N–H
amide carbonyl
Question 6
I
Match the ortho, meta and para
isomers of xylene.
II
III
ortho
meta
para
A)
I
II
III
B)
II
I
III
C)
I
III
II
D)
III
II
I
Answer
I
C)
I
III
II
II
III
Ortho 735-770
Para 790-840
Meta 750-810 and 680-730
Question 7
C8H8O2
Identify the compound from the IR above.
A)
B)
C)
D)
methylbenzoate
phenylacetate
p-anisaldehyde
o-anisaldehyde
Answer
Identify the compound from the IR above.
A) methylbenzoate
B) Phenylacetate
C) p-anisaldehyde
D) o-anisaldehyde
Question 8
• Which proton is most shielded?
•
A) CHCl3
•
B) CH2Cl2
•
C) CHBr3
•
D) CBr4
Answer
• Which proton is most shielded?
•
A) CHCl3
•
B) CH2Cl2
•
C) CHBr3
•
D) CBr4
Question 9
• Select the most shielded proton in 1,1,2trichlorobutane.
•
A) 1
•
B) 2
•
C) 3
•
D) 4
Answer
• Select the most shielded proton in 1,1,2trichlorobutane.
•
A) 1
•
B) 2
•
C) 3
•
D) 4
Question 10
• Assign the chemical shifts d 1.6,
•
d 2.2, and d 4.8 to the appropriate
protons of methylene cyclopentane.
•
A) x = 1.6; y = 2.2; z = 4.8
•
B) x = 4.8; y = 1.6; z = 2.2
•
C) x = 1.6; y = 4.8; z = 2.2
•
D) x = 2.2; y = 1.6; z = 4.8
Answer
• Assign the chemical shifts d 1.6,
•
d 2.2, and d 4.8 to the appropriate
protons of methylene cyclopentane.
•
A) x = 1.6; y = 2.2; z = 4.8
•
B) x = 4.8; y = 1.6; z = 2.2
•
C) x = 1.6; y = 4.8; z = 2.2
•
D) x = 2.2; y = 1.6; z = 4.8
Question 11
• Assign the chemical shifts d1.1,
•
d2.4, and d9.7 to the appropriate
protons of propanal.
•
A) x = 2.4; y = 1.1; z = 9.7
•
B) x = 1.1; y = 9.7; z = 2.4
•
C) x = 9.7; y = 2.4; z = 1.1
•
D) x = 1.1; y = 2.4; z = 9.7
Answer
• Assign the chemical shifts d1.1,
•
d2.4, and d9.7 to the appropriate
protons of propanal.
•
A) x = 2.4; y = 1.1; z = 9.7
•
B) x = 1.1; y = 9.7; z = 2.4
•
C) x = 9.7; y = 2.4; z = 1.1
•
D) x = 1.1; y = 2.4; z = 9.7
Question 12
A compound with the formula C6H14O has the following
signal integration for 3 signals: A, B, and C. How many
protons are represented by each signal?
A. Signal at 0.9, integration of 6.3
B. Signal at 1.4, integration of 4.2
C. Signal at 3.5, integration of 4.2
A. A = 3; B = 4; C = 4
B. A = 3; B = 2; C = 2
C. A = 6; B = 2; C = 2
D. A = 6; B = 4; C = 4
Answer
A compound with the formula C6H14O has the following
signal integration for 3 signals: A, B, and C. How many
protons are represented by each signal?
A. Signal at 0.9, integration of 6.3
B. Signal at 1.4, integration of 4.2
C. Signal at 3.5, integration of 4.2
A. A = 3; B = 4; C = 4
B. A = 3; B = 2; C = 2
C. A = 6; B = 2; C = 2
D. A = 6; B = 4; C = 4