Quiz 3.21

Question 1

1. Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the highest energy?
   A. radio waves
   B. ultraviolet
   C. infrared
   D. visible

Answer 1

B. ultraviolet

Question 2

2. Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the longest wavelength?
   A. radio waves
   B. ultraviolet
   C. infrared
   D. visible

Answer 2

A. radio waves

Question 3

3. What range of wavelengths corresponds to the infrared region of the electromagnetic spectrum?
   A. 200-400 nm
   B. 400-700 nm
   C. 2.5-50 mm
   D. 2-10 mm

Answer 3

C. 2.5-50 mm

Question 4

4. Which of the following processes takes place upon absorption of infrared radiation?
   A. bond vibration
   B. electron excitation
   C. nuclear spin flip
   D. electron spin flip

Answer 4

A. bond vibration

Question 5

5. What are the units of wavenumber, , in infrared spectroscopy?
   A. cm
   B. cm-1
   C. Jmol-1
   D. none, wavenumber is a dimensionless quantity

Answer 5

B. cm-1

Question 6

6. Which of the following relationships is not valid as applied to infrared spectroscopy?
   A. wavenumber = 1/l (in cm)
   B. DE = h n
   C. DE = l n
   D. n = 4.12 Ö(K/m)

Answer 6

C. DE = l n

Question 7

7. Which of the following laws relates the frequency of a stretching vibration to the masses and spring constant of a simple harmonic oscillator?
   A. Pan’s law
   B. Hooke’s law
   C. Peter’s law
   D. Barrie’s law

Answer 7

B. Hooke’s law

Question 8

8. What is required for a bond to give an infrared absorption?
   A. a change in bond length during vibration
   B. a change in bond angle during vibration
   C. a change in bond dipole during vibration
   D. a change in reduced mass during vibration

Answer 8

C. a change in bond dipole during vibration

Question 9

9. Which of the following bonds (circled) gives a very weak or no stretching absorption in the infrared spectrum?

Answer 9

A. 1

Question 10

10. Which of the following bonds gives the weakest peak in the infrared spectrum for a stretching vibration?

Answer 10

B. 2

Question 13

11. Which of the following bonds undergoes stretching at the highest frequency?
    A. C=O
    B. C-O
    C. C=C
    D. C-C

Answer 13

A. C=O

Question 14

14. Which of the following bonds (circled) vibrates at the highest frequency?

Answer 14

D. 4

Question 15

15. Which of the following bonds (circled) gives the weakest absorbance in the infrared spectrum?

Answer 15

B. 2

Question 16

12. Which of the following bonds undergoes stretching at the highest frequency?
    A. O-H
    B. C-H
    C. C=O
    D. CºC

Answer 16

A. O-H

Question 17

13. Which of the following carbon-carbon bonds undergoes stretching at the highest frequency?
    A. sp3 C - sp3 C
    B. alkene sp2 C - sp2 C
    C. arene sp2 C - sp2 C
    D. CºC

Answer 17

D. CºC

Question 20

16. Which of the following bonds gives rise to a strong absorbance at approximately 1630-1820 cm-1 in the infrared spectrum?
    A. C=O
    B. C-O
    C. C=C
    D. CºC

Answer 20

A. C=O

Question 21

17. Which of the following bonds gives rise to an absorbance at approximately 2700-3300 cm-1 in the infrared spectrum?
    A. CºC
    B. C=O
    C. C=C
    D. C-H

Answer 21

D. C-H

Question 22

18. Which of the following bonds gives rise to a strong, broad, absorbance at approximately 3200-3650 cm-1 in the infrared spectrum?
    A. C=O
    B. O-H
    C. C=C
    D. C-H

Answer 22

B. O-H

Question 23

19. Which of the following bonds gives rise to a medium strength absorbance at approximately 1600-1680 cm-1 in the infrared spectrum?
    A. C-H
    B. C-C
    C. C=C
    D. CºC

Answer 23

C. C=C

Question 24

24. Which of the following compounds gives an infrared spectrum with peaks in the ranges of 3200-3650 (strong, broad) and 1600-1640 cm-1 (medium); but does not have peaks at 1630-1820 (strong)?

Answer 24

C. 3

Question 25

25. Which of the following compounds gives an infrared spectrum with a peak in the range of 1630-1820 cm-1 (strong peak), but does not have peaks at 3200-3650 or 1000-1250 cm-1?

Answer 25

B. 2

Question 26

Answer 26

A. 1

Question 27

Answer 27

D. 4

Question 28

Answer 28

A. 1

Question 29

Answer 29

B. 2

Question 30

Answer 30

C. 3

Question 31

Answer 31

B. 2

Question 32

Answer 32

A. 1

Question 33

Answer 33

A. 1

Question 34

Answer 34

C. 3

Question 35

Answer 35

B. 2

Question 36

20. Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1630-1820 cm-1 (strong, broad) and 1000-1250 cm-1; but does not have peaks at 3200-3650 cm-1? A. alcohol B. aldehyde or ketone C. ether D. ester

Answer 36

D. ester

Question 37

21. Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1630-1820 cm-1 (strong, broad), but does not have peaks at 3200-3650 or 1000-1250 cm-1 A. alcohol B. aldehyde or ketone C. ether D. ester

Answer 37

B. aldehyde or ketone

Question 38

22. Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 3200-3650 cm-1 (strong), but does not have peaks at 1630-1820 or 1000-1250 cm-1 A. alcohol B. aldehyde or ketone C. ether D. ester

Answer 38

A. alcohol

Question 39

23. Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1000-1250 cm-1 (strong), but does not have peaks 3200-3650 at 1630-1820 or cm-1? A. alcohol B. aldehyde or ketone C. ether D. ester

Answer 39

C. ether