1. Infrared / NMR Spectroscopy Questions1

2. Is the following IR of cis or trans 2-pentene?
Question 1
Is the following IR of cis or trans 2-pentene?
cis B) trans

3. Is the following IR of cis or trans 2-pentene? B) trans 2-pentene
Answer
Is the following IR of cis or trans 2-pentene? B) trans 2-pentene

4. Question 2 Identify the compound from the IR above. benzyl alcohol
C7H6O
Identify the compound from the IR above.
benzyl alcohol
1,4,6-heptatrien-3-one
2,4,6-heptatrienaldehyde
benzaldehyde

5. Answer D) Benzaldehyde wavenumber (cm–1) assignment 2810 and 2730
1700
an aldehyde
mono subs benzene
carbonyl

6. Question 3 Identify the compound from the IR above.
C10H12O
Identify the compound from the IR above.
4-phenylbutanaldehyde
phenylpropyl ketone
meta-isopropylbenzaldehyde
1-phenyl-2-butanone

7. non-conj ketone carbonyl
Answer
D) 1-phenyl-2-butanone
wavenumber (cm–1) assignment
>3000
<3000
740 and 700
1720
sp2 CH
sp3 CH
Mono subs benzene ring
non-conj ketone carbonyl

8. Question 4 Identify the compound from the IR above. cyclopropanone
C3H4O
Identify the compound from the IR above.
cyclopropanone
propynol
2-cyclopropenol
1,2-propadienol

9. Answer B) propynol wavenumber (cm–1) assignment 3300 OH group 2950
2100
OH group
sp3 CH
alkyne

10. Question 5 Identify the compound from the IR above. N-methylacetamide
C3H7NO
Identify the compound from the IR above.
N-methylacetamide
N,N-dimethylformamide
3-aminopropanal
N-methylamino-ethanal

11. Answer N-methylacetamide wavenumber (cm–1) assignment 3300 N–H 1660
amide carbonyl

12. Question 6 I II III Match the ortho, meta and para isomers of xylene.B) C) D)

13. Answer I II III Ortho 735-770 Para 790-840 Meta 750-810 and 680-730 C)

14. Question 7 Identify the compound from the IR above. methylbenzoate
C8H8O2
Identify the compound from the IR above.
methylbenzoate
phenylacetate
p-anisaldehyde
o-anisaldehyde

15. Answer Identify the compound from the IR above. methylbenzoate
Phenylacetate
p-anisaldehyde
o-anisaldehyde

16. Question 8 Which proton is most shielded? A) CHCl3 B) CH2Cl2 C) CHBr3
D) CBr4

17. Answer Which proton is most shielded? A) CHCl3 B) CH2Cl2 C) CHBr3
D) CBr4

18. Question 9 Select the most shielded proton in 1,1,2-trichlorobutane.

19. Answer Select the most shielded proton in 1,1,2-trichlorobutane. A) 1

20. 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

21. 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

22. 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

23. 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

24. 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 = 3; B = 4; C = 4
A = 3; B = 2; C = 2
A = 6; B = 2; C = 2
A = 6; B = 4; C = 4

25. 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 = 3; B = 4; C = 4
A = 3; B = 2; C = 2
A = 6; B = 2; C = 2
A = 6; B = 4; C = 4