Chapter 10 Acid/Base Chemistry
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Chapter 10 Acid/Base Chemistry
Acid Vs Base
Characteristics of Acids:
•  Sour taste
•  Change blue litmus paper red; red litmus paper does not change
•  Produce hydronium ions (H3O+) when dissolved in water by donation of H+
•  Acids produce positively and negatively charged ions in aqueous solution; thus acidic solutions
conduct electricity and are electrolytes!
Characteristics of Bases:
•  Bitter taste
•  Turn red litmus paper blue; blue litmus paper does not change
•  Produce hydroxide ions (OH-) when dissolved in water by accepting H+
•  Bases produce positively and negatively charged ions in aqueous solution; thus basic solutions
conduct electricity and are electrolytes!
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Chapter 10 Acid/Base Chemistry
Strong Vs Weak
Strong acids and bases will completely dissociate in water.
Strong Acids:
•  HCl
•  HBr
•  HI
•  HNO3
•  H2SO4
•  HClO4
Strong Bases:
•  Group IA and IIA metal hydroxides
Some substances can behave as either an acid or a base, depending on the circumstances, and are
called amphoteric substances.
Recall that an acid and a metal hydroxide base will react in a neutralization reaction to form a salt and
water.
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Chapter 10 Acid/Base Chemistry
pH Scale
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The pH of a solution is a measure of the H3O+ concentration in moles/L (M).
If the hydronium ion concentration is known, the pH can be found from:
pH = - log [H3O+]
Note that the hydronium ion concentration is just the acid concentration for
any strong acid since strong acids 100% dissociate in aqueous solution.
If the pH is known, the hydronium ion concentration can be found from:
[H3O+] = 10-pH
Since pH is a log scale, a one unit increase in pH is a 10 fold decrease in the
[H3O+] concentration
A one unit decrease in pH is a 10 fold increase in the [H3O+] concentration.
Problems:
1. A sample of lemon juice has a [H3O+] of 3.8x10-4 M. What is the pH?
2.  A common window-cleaning solution has a [H3O+] of 5.3x10-9 M. What is the
pH? Is this acidic, basic, or neutral?
3. Fresh, homemade apple juice was found to have a pH of 3.76. What is the
[H3O+]?
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Chapter 10 Acid/Base Chemistry
Buffers
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Buffer: A solution that resists a change in pH when a moderate amount of acid or base is added.
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A buffer can only work if there is both a weak acid and it’s conjugate base present in solution.
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In a conjugate acid-base pair the acid will always contain one H more than it’s conjugate base.
Examples:
•  HC2H3O2/NaC2H3O2
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H3PO4/NaH2PO4
Chapter 10 Acid/Base Chemistry
Acid Rain
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Rainfall is naturally acidic due to carbon dioxide in the air:
CO2(g) + H2O(l) ! H2CO3(aq)
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Sulfur oxides and nitrogen oxides as pollutants from auto emissions and industrial processes can
lead to formation of acid rain:
SO2(g) + H2O(l) ! H2SO3 (aq)
SO3 (g) + H2O(l) ! H2SO4 (aq)
2NO2 (g) + H2O(l) ! HNO3 (aq) + NO(aq)
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Chapter 10 Acid/Base Chemistry
What is the chemical formula for the base iron(III) hydroxide?
The formula for the oxalate ion is
. Predict the formula for oxalic acid.
What is the pH of an aqueous solution with
?
Carbonated cola is more acidic than coffee or even orange juice because cola contains phosphoric acid. What is
the molar concentration of
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in a cola that has a pH of 3.120?
Chapter 10 Acid/Base Chemistry
How many moles of
are present in 105 mL of 0.200 ?
What substance would you add to KF (aq) in order to form a buffer solution?
KCl
HClO
HF
NaF
KOH
NaCl
NH3
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Chapter 10 Acid/Base Chemistry
The H3O+ ion is called the ________ ion.
hydroxide
protium
hydrogen
water
hydronium
When acids and bases react the product other than water is a
hydroxide ion.
hydronium ion.
salt.
metal.
hydrogen ion.
Which of the following compounds is a salt?
H2SO4
NaOH
HBr
C6H12O6
KNO3
A Brønsted-Lowry acid is a substance which
accepts protons from other substances.
donates protons to other substances.
accepts hydronium ions from other substances.
produces hydrogen ions in aqueous solution.
produces hydroxide ions in aqueous solution.
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Chapter 10 Acid/Base Chemistry
A Brønsted-Lowry base is a substance which
accepts protons from other substances.
produces hydrogen ions in aqueous solution.
donates protons to other substances.
produces hydroxide ions in aqueous solution.
accepts hydronium ions from other substances.
Which of the following is a diprotic acid?
acetic acid
sulfuric acid
hydrochloric acid
phosphoric acid
nitric acid
What is the conjugate base of HSO4-?
H3O+
OHH2SO3
H2SO4
SO42C5H5N + H2CO3 ↔ C5H6N+ + HCO3In the reaction shown, the conjugate acid of C5H5N is ________.
C5H6N+
H3O+
H2CO3
HCO3C5H5N
Which of the following cannot act as a Brønsted base?
NH4+
HCO3NH2NH3
CO32What is the conjugate acid of HSO4-?
H2SO3
OHSO42H2SO4
H3O+
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Chapter 10 Acid/Base Chemistry
Which equation correctly represents the neutralization of aluminum hydroxide by sulfuric acid?
Al(OH)3 + H3SO4 → AlSO4 + 3 H2O
3 Al(OH)3 + 2 H3SO4 → Al3(SO4)2 + 6 H2O
Al(OH)2 + H2SO4 → AlSO4 + 2 H2O
2 Al(OH)3 + 3 H2SO4 → Al2(SO4)3 + 6 H2O
2 Al(OH)3 + 3 H2SO4 → Al2(SO4)3 + 3 H2O
Acetic acid is a weak acid in water because it is
unable to hold onto its hydrogen ion.
completely dissociated into hydronium ions and acetate ions.
only slightly dissociated into ions.
dilute.
only slightly soluble.
Which of the following is a strong acid?
HCO3HNO3
NH4+
H2O
H3PO4
Which of the following is a weak acid?
HNO3
HCl
NH3
OHH3PO4
Which reaction best illustrates the behavior of the weak base H2PO4- in aqueous solution?
H2PO4- (aq) + H+ (aq) ↔ H3PO4 (aq)
H2PO4- (aq) + H2O (l) ↔ H3PO4 (aq) + OH- (aq)
H2PO4- (aq) + H2O (l) ↔ HPO42- (aq) + H3O+ (aq)
H2PO4- (aq) ↔ 2H+ (aq) + PO43- (aq)
H2PO4- (aq) ↔ H+ (aq) + HPO42- (aq)
Which one of the following is the weakest acid?
HClO (Ka = 3.0 x 10-8)
HCN (Ka = 4.9 x 10-10)
HNO2 (Ka = 4.5 x 10-4)
HF (Ka = 6.8 x 10-4)
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Chapter 10 Acid/Base Chemistry
Which compound has a very large value of Ka in aqueous solution?
KOH
HNO3
H3PO4
NH3
NaCl
Which solution is basic?
[H3O+]= 1.0 × 10-4
[OH-] = 1.0 × 10-10
[OH-] = 1.0 × 10-7
[H3O+]= 1.0 × 10-7
[H3O+]= 1.0 × 10-10
What is the pH of a solution in which [H3O+] = 3.8 × 10-8 M?
2.6 x 10-7
7.42
6.58
1.0 x 10-8
3.80
What is the hydrogen ion concentration in a solution with pH = 2.34?
1.17 × 101 M
4.27 × 10-12 M
2.19 × 10-12 M
2.34 × 10-3 M
4.57 × 10-3 M
Which of the following pH's corresponds to a strongly basic solution?
11.5
4.3
7.4
2.7
6.9
Which of the following pH's corresponds to a neutral solution?
8.5
6.2
7.0
1.8
14.0
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Chapter 10 Acid/Base Chemistry
Which of the following pH's corresponds to a weakly acidic solution?
5.3
9.2
7.8
1.4
11.5
A buffer solution
is a salt solution.
is a strong base.
neutralizes only acids.
closely maintains its original pH.
maintains pH at 7.00.
Which of the following solutions is a buffer?
a solution of sulfuric acid and sodium sulfate
a solution of acetic acid and sodium sulfate
a solution of acetic acid and sodium acetate
a solution of hydrochloric acid and sodium acetate
a solution of hydrochloric acid and sodium sulfate
How many mL of 0.100 M NaOH are needed to neutralize 24.0 mL of 0.150 M HCl?
18.0 mL
48.0 mL
36.0 mL
24.0 mL
12.0 mL
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