Conjugados Ácidos e Bases

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Solutions for Introduction and Review
51 continued
(c) The weakest conjugate acid will form the strongest conjugate base.
OH
strongest base
> CH3CH2 N H
H
CN
H
H
O
CH3
> > CH3CH2 O H
weakest base
H3C
C
O
O
H3C
C
O
O
52 (a) conjugate bases
H3C
C
NH
O
H3C
C
NH
O
H3C
S
O
O
H3C
S
O
O
OSH3C
O
O
OSH3C
O
O
OSH3C
O
O
>
OSF
O
O
OSF
O
O
OSF
O
O
(b)
OSH3C
O
O
delocalization of 
negative charge by 
three resonance 
forms and 
induction (S more 
electronegative 
than C)
>
H3C
S
O
O
delocalization of 
negative charge by 
two resonance forms 
and induction (S 
more electronegative 
than C)
>
H3C
C
O
O
delocalization of 
negative charge by 
two equivalent 
resonance forms
H3C
C
NH
O
>
least stable—
delocalization of 
negative charge by 
two resonance 
forms, although 
non-equivalent
(c) The strongest acid will have the most stable conjugate base. The pKa values are listed beneath each acid.
OHSH3C
O
O
>
H3C
S
OH
O
>
H3C
C
OH
O
H3C
C
NH2
O
>
weakest acid
pKa –1.2 pKa 4.7
pKa 16
pKa 2.3
OSF
O
O
most stable—
delocalization of 
negative charge by 
three resonance 
forms and 
induction (F and S 
more electro-
negative than C)
>
OHSF
O
O
strongest acid
>
pKa