Chemistry Reference
In-Depth Information
Q 6.3.
The amide ion (H
2
N
−
) is a stronger base than hydroxide. Which of the
conjugate acids, NH
3
or H
2
O, is stronger?
Q 6.4.
Ammonia has
pK
a
33 and propanone has
pK
a
20. Can the following
reaction occur as drawn?
Q 6.5.
Can the bicarbonate anion deprotonate methanol as shown in the fol-
lowing equation?
PROGRAM 17 Acidity/Basicity and Resonance
A So far we have decided acid and base strength by using known
pK
a
values. If the
pK
a
value is not known, you can use the resonance and inductive electronic effects to
explain differences in acid and base strength. This program deals with the important
role of resonance.
A comparison of the acid strengths of ethanol and ethanoic acid is a good example to
show the concept. To do this, we need to compare the equilibria:
A good place to start is with the possible resonance forms of the species.
Draw and compare the possible resonance structures.
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