Conjugate Acid-Base Pairs

1
Conjugate Acid-Base Pairs
2
Acid Dissociation
H
Cl
HCl
Conjugate base
Acid
Conjugate pair
Kelter, Carr, Scott, Chemistry A World of
Choices 1999, page 280
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Conjugate Acid-Base Pairs
conjugates
base
acid
acid
base
conjugates
4
Conjugate Acid-Base Pairs
conjugates
acid
base
base
acid
conjugates
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Water is Amphoteric
Amphoteric or Amphiprotic substances
Substances which can act as either proton donors
(acids) or proton acceptors (bases) depending on
what substances are present.
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Amphoteric
A substance that can act as either an acid or a
base.
1-
1


H2O
H3O
H2SO4
HSO4-
water
hydrogen sulfate ion
hydronium ion
sulfuric acid
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Amphoteric
A substance that can act as either an acid or a
base.
1-
1

H3O
HSO4-
hydrogen sulfate ion
hydronium ion
(HSO4- as a base)
8
Amphoteric
A substance that can act as either an acid or a
base.
1-
1-

HSO4-
OH-
hydrogen sulfate ion
hydroxide ion
(HSO4- as an acid)
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Conjugate Acid-Base Pairs
base2
acid2
acid1
base1
The reaction proceeds in the direction such that
the stronger acid donates its proton to the
stronger base.