Organic Chemistry

518 CHAPTER 13 Mass Spectrometry and Infrared Spectroscopy

g. j. and

h. k.

i. cis-2-butene and trans-2-butene l.

33. a. How could you determine by IR spectroscopy that the following reaction had occurred?

b. After purifying the product, how could you determine that all the had been removed?

34. What identifying characteristics would be present in the mass spectrum of a compound containing two bromine atoms?


35. Assuming that the force constant is approximately the same for and bonds, predict the relative positions of
    their stretching vibrations.


36. A mass spectrum shows significant peaks at 115, 140, and 143. Which of the following compounds is responsible for
    that mass spectrum: 4,7-dimethyl-1-octanol, 2,6-dimethyl-4-octanol, or 2,2,4-trimethyl-4-heptanol?


37. How could IR spectroscopy distinguish between 1,5-hexadiene and 2,4-hexadiene?


38. A compound gives a mass spectrum with peaks at (40%), 112 (100%), 114 (33%), and essentially no other peaks.
    Identify the compound.


39. What hydrocarbons will have a molecular ion peak at


40. In the following boxes, list the types of bonds and the approximate wavenumber at which each type of bond is expected to show an
    IR absorption:


41. For each of the IR spectra in Figures 13.35, 13.36, and 13.37, four compounds are shown. In each case, indicate which of the four
    compounds is responsible for the spectrum.

a.

O

CH 3 CH 2 CH 2 C CCH 3 CH 3 CH 2 CH 2 CH 2 OH CH 3 CH 2 CH 2 CH 2 CCHCH 3 CH 2 CH 2 COH

Wavenumber (cm−^1 )

3600 3000 1800 1400 1000

m>z=112?

m>z= 77

m>z=87,

C¬C,C¬N, C¬O

NH 2 NH 2

CH 3

O

CH

NH 2 NH 2

HO–, ∆

H and C H

O

C

O

OO

CH 3 CH 2 CNH 2 and CH 3 CH 2 COCH 3

O O

and

CH 3 CH 2 CH 2 OH CH 3 CH 2 OCH 3

OO

CH 3 CH 2 CH and CH 3 CH 2 CCH 3