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476 Chapter 14
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c.
frequency
a
b
b a
ClCH
2
CH
2
OH
d.
frequency
a
b
e.
CH
3
carbons
CH
2
carbons
CH carbons
all carbons
70.
If addition of HBr to propene follows the rule that says that the electrophile adds to the
sp
2
carbon that is
bonded to the most hydrogens, the product of the reaction will give an NMR spectrum with two signals
(a doublet and a septet). If addition of HBr does not follow the rule, the product will give an NMR spec-
trum with three signals (two triplets and a multiplet).
CH
3
CH CH
2
+
HBr
CH
3
CH
2
CH
2
Br
does not follow the rule
two signals
three signals
CH
3
CHCH
3
Br
follows the rule
71.
a.
b.
O
c.
O
d.
O
72.
Bromomethane gives a signal at 2.7 ppm for its three methyl protons, and 2-bromo-2-methylpropane gives
a signal at 1.8 ppm for its nine methyl protons. If equal amounts of each were present in a solution, the
ratio of the hydrogens (and, therefore, the ratio of the relative integrals) would be 3:1. Because the relative
integrals are 1:6, there must be an 18-fold greater concentration of bromomethane in the mixture.
3 :
x
=
1 : 6
x
=
18