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8.6 Acid-Base Properties of Salt Solutions
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A salt is an ionic compound containing a cation (+ ion) and an anion (- ion)
they are produced in neutralization reactions
salts can be _______________, _________________ or ___________________
the pH is dependent upon whether the cation and anion are conjugates of strong or weak acids
and bases
the cation comes from the _________________ and the anion comes from the _____________
Strong Acids:
Weak Acids:
Strong Bases:
Weak Bases:
HCl HBr HI HNO3 H2SO4 HClO4
all other H ___
metal + OHall other, ex NH3 CH3NH2 C5H5N
Recall:
 A strong acid or base will have a conjugate with negligible acid/base properties (it will
not react with water)

HCl
+
NaOH
+

H2O
H2O

H3O+
+
Cl-
NaOH2+
+
OH-
A weak acid or base will produce a conjugate that has weak acid/base properties (it
will react with water)
HCH2H5O2
NH3
+
+
H2O

H3O+
+
CH2H5O2-
H2O

NH4+
+
OH-
Salts that Produce Neutral Solutions…
Ex: NaCl, Ca(NO3)2, KBr
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Cation (eg Na+) is the conjugate of a __________ base (eg NaOH) and therefore has
______________ acidic properties.
Anion is the conjugate of a ___________ acid (eg HCl) and therefore has
________________ basic properties.
Neither of the ions act as an acid or a base and thus the pH is _________________
a salt produced in the reaction of a ______________________ and ___________________
will be _____________________
Salts that Produce Acidic Solutions…
Ex: NH4Cl

Cation (NH4+) is the __________ conjugate acid of a ___________ base (NH3). This
conjugate acid would thus react with water to produce H3O+.
NH4+ + H2O  NH3 + H3O+

Anion (Cl-) is the conjugate of a ____________ acid (eg HCl) and therefore would have
negligible basic properties.
Cation acts as an acid; anion has no effect on pH
a salt produced in the reaction of a _____________________ and _____________________
will be ______________________
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
Ex)
What is the pH of a 0.35 M NH4Cl solution?
(Kb for ammonia is 1.8x10-5)
Salts that Produce Basic Solutions…
Ex: NaCH3COO
•
Anion (CH3COO-) is the __________ conjugate base of a _________ acid (CH3COOH). This
conjugate base would thus react with water to produce OH-.
CH3COO- + H2O  CH3COOH + OH-
•
Cation is the conjugate of a ___________ base (eg NaOH) and therefore will have negligible
acidic properties.
Anion acts as an base; cation has no effect on pH
a salt produced in the reaction of a ______________________ and ____________________
will be _____________________
•
•
Ex)
Calculate the pH of a solution that contains 12.5g of sodium acetate (NaCH3COO) dissolved
in 1.0L of H2O. (Ka for acetic acid is 1.8x10-5)
What about if the salt contained an ion that is AMPHOTERIC?
Ex)
Is the solution of KH2PO4 acidic or basic?
Ex)
Sort the following salts based on whether they form acidic, neutral, or basic solutions when
dissolved in water.
NaCl
NH4NO3
NaClO
C5H5NHCl
Self Check
How prepared am I to start my homework? Can I …
… determine the pH of a solution containing a salt
LiF
0
1
KCN
2
3
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8.6 Acid-Base Properties of Salt Solutions