Chapter 5 The Covalent Bond
104
H CH H
OC
H
H
H
C C
C
N C
C
H H
H
H
H
OC
H
H C H
H
HP
H
H
a)
b)
c)
d)
39.
Lone pairs are often left out of molecular drawings, but, as we shall see in Chapter 6, they are important in determining the shape of the molecule. Indicate any missing lone pairs in th
e following. (Assume that all atoms
except H obey the octet rule.)
38.
Add double bonds to the Lewis structure of naphthalene (C
H 10
, see top of 8
page for the Lewis structure), the active ingredient in mothballs, so that each carbon atom has an octet. How
many resonance structures can be
drawn for naphthalene? Estimate the le
ngths of the carbon-carbon bonds.
a) Hint: refer to Table 5.3 and the discussion in Section 5.7.
Use the method of Section 4.4 to determine the oxidation state of the carbon.
b)
Use the Lewis structure of the com
pound shown in the margin and the
method presented in Section 5.8 to determine the oxidation state of each carbon atom in C
H 2
O. Does either carbon have the oxidation 4
state derived in part a?
Use the following Lewis struct
ures for Exercises 36-38.
H CH H
H
C
O C
H
H CH
OHC
C C
C C
C
C C
C
H
HH
H
C
Exercise 36
Exercise 37
Exercise 38
H
H
H
H
36.
In compounds with more than one atom of the same type, the oxidation state of those atoms derived from the procedure presented in Section 4.4 leads to the average oxida
tion state of the atom, not the oxidation states of
the individual atoms. For example, consider the molecule C
H 2
O. 4
b) Use the Lewis structure of acetic acid shown to the right and the
method presented in Section 5.8 to determine the oxidation state of each carbon atom in HC
H 2
O 3
. Does either carbon have the oxidation 2
state derived in part a?
a) Use the method of Section 4.4 to determine the oxidation state of the
carbon.
37.
Apply the discussion given in Exercise 36 to acetic acid, HC
H 2
O 3
(See 2
above for the Lewis structure.)
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