2/27/2012
Acids
Bases
Taste sour
Taste Bitter
Burn Skin
Burn Skin/Feel Slippery
Turn Litmus Red
Turn Litmus Blue
Dissolve metals
Citrus fruit
Vitamin C (Ascorbic Acid)
Vinegar
Battery Acid
Acid-Base
Acid-Base Behavior
Definitions of Acids/Bases
A. Arrhenius
B. Bronsted/Lowry
C. Lewis
Soap
Ammonia
Baking Soda
Tums
Drano
Acid-Base
Acid-Base
Arrhenius Definition
A. Acids – Produce H3O+ (H+) in water
B. Bases – Produce OH- in water
C. Examples
HCl + H2O 
HNO3 + H2O 
HClO4 + H2O 
Acid-Base
Acid-Base
Arrhenius Definition
HBr + H2O 
NaOH 
KOH 
Ba(OH)2 
D. H3O+ - hydronium ion
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Acid-Base
Acid-Base
Arrhenius Definition
Acid-Base
D. Examples
Bronsted-Lowry Definition
A. Acid – H+ (proton) donor
B. Base - H+ (proton) acceptor
C. Works even if water is not present
HCl + H2O 
Bronsted-Lowry Definition
NH3 + H2O 
HC2H3O2 + H2O 
OCl- + H2O 
Acid-Base
Acid-Base
Bronsted-Lowry Definition
NH3 + H2PO4- NH4+ + HPO42What is the conjugate base of:
HClO4
H2S
PH4+
HCO3What is the conjugate acid of:
CNSO42H2O
HCO3E. Amphiprotic – acts as either an acid or base (H2O)
Water and Kw
1. Autoionization of H2O
2H2O(l)  H3O+(aq) + OH-(aq)
2. Kw = [H3O+][OH-]/[H2O]2
Kw = [H3O+][OH-]
Kw = 1 X 10-14
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Acid-Base
Acid-Base
Kw and pH
Kw and pH
H3
1. Kw = [H3O+][OH-] All aqueous solns
contain BOTH H3O+ and OH-.
2. Acidic solns contain more
H3O+(hydronium ion)
3. Basic solns contain more OH- (hydroxide)
4. Neutral solution H3O+ = OH-
O+
OH-
A/B?
2 X 10-5
2.5 X 10-6
3 X 10-9
4.8 X 10-8
100X [OH-]
Neutral
Acid-Base
pH
1. Measure of acidity/basicity(alkalinity)
0-6.99
Acidic
7
Neutral
7.01 – 14 Basic/Alkaline
2. Logarithmic Scale
pH = 2
[H3O+] = 0.01 M
pH = 1
[H3O+] = 0.1 M
Acid-Base
13
12
11
10
9
8
7
Oven Cleaner/Drano
Hair remover
Ammonia
Soap
Baking Soda, bleach, antacids
Shampoo
Water, blood, eggs, baby shampoo
Acid-Base
pH
3. Each change in pH is a factor of 10
(Richter scale is also logarithmic)
4. Indicators
pH
Acid-Base
6
5
4
3
2
1
pH
Urine, milk, saliva
Coffee, bread, rainwater
Tomatoes
Vinegar, soda, beer
Stomach acid, lemon juice
Battery acid
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Acid-Base
Acid-Base
pH vs. log[H3O+]
pH vs. [H3O+]
6
6
5
5
4
3
pH
pH
4
3
Series1
2
2
1
1
0
-0.02
0
0.02
0.04
0.06
0.08
0.1
0.12
0
[H3O+]
-6
Acid-Base
pH Formula
1. pH = -log [H3O+]
2. Examples
What is the pH if the [H3O+] of a
solution is 1 X 10-12?
What is the pH if the [H3O+] of a
solution is 5.0 X 10-6? (5.3)
Acid-Base
pH Formula
-5
[H3
[OH-]
-3
log[H3O+]
-2
Acid-Base
-1
0
pH Formula
What is the [H3O+] of a solution if the pH =
3.76?
What is the [H3O+] of a solution if the pH =
9.18?
3. pOH = -log [OH-]
pH + pOH = 14
pH = -log [H3O+]
Kw = [H30+][OH-]
Acid-Base
H3O+
O+]
-4
OH-
pH Formula
pH
pOH
A or B
7 X 10-10
6 X 10-10
9.4
pH
pOH
5.2
8.7
6.2
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Acid-Base
Strong Acids
1. Completely (100%) dissociates in water
2. Low pH and no Ka, single arrow
3. Common Strong Acids
HCl HBr HI
HNO3
H2SO4
HClO4
Acid-Base
Strong Acids
1. What is the pH of 0.040 M HCl?
(Ans: 1.40)
2. What is the pH of 0.0040 M HNO3?
(Ans: 2.40)
Acid-Base
Strong Bases
1. Soluble Hydroxides. Completely
(100%) dissociate in water
2. High pH and no Kb
Acid-Base
Strong Acids
Eqn/Species
HCl + H2O 
HNO3 + H2O 
H2SO4 + H2O 
(just one proton)
Acid-Base
Strong Acids
3. A soln of HNO3 has a pH of 2.66. What
is the conc. of the acid? (Ans: 0.0022 M)
4. A soln of HBr has a pH of 3.55. What is
the conc. of the acid? (Ans: 0.000282 M)
Acid-Base
Strong Bases
3. Common Strong Bases
NaOH 
KOH 
Ba(OH)2 
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Acid-Base
Strong Bases
1. What is the pH of 0.011 M NaOH?
(Ans: 12.0)
2. What is the pH of 0.011 M Ca(OH)2?
(Ans: 12.3)
3. What is the molarity of a soln of KOH
that has a pH of 11.89? (Ans:
0.007763)
Acid-Base
Weak Acids
Eqn/Species/Ka
HC2H3O2 + H2O 
HNO2 + H2O 
Acid-Base
Weak Acids
1. Do not completely dissociate in water. Higher
pH.
2. Equilibrium. Has a Ka
3. Some Common Weak Acids
HC2H3O2 Acetic
H3PO4
Phosphoric
H2CO3
Carbonic
HC6H7O6 Ascorbic
Acid-Base
Weak Acids
1. What is the pH of 0.100 M HC2H3O2?
(Ans: 2.9)
2. What is the pH of 0.100 M HC3H5O3?
(Ans: 2.4)
HSO4- + H2O 
“The larger the Ka, the stronger the acid.”
Acid-Base
Weak Acids
3. What is the Ka of HCN if a 0.20 M soln
has a pH of 5.00? (Ans: 5.0 X 10-10)
4. What is the Ka of HF if a 0.10 M soln
has a pH of 2.1? (Ans:6.8 X 10-4)
We buy a gallon of vinegar (acetic acid) and find
the pH to be 3.74.
a. Calculate the molarity of the acid. (0.00202 M)
b. Calculate the grams of acetic acid present in 1
quart of vinegar (1 L = 1.0567 qt). (0.115)
c. Calculate the pH of 0.0200 M acetic acid. (1.7)
d. Draw a Lewis Dot structure of acetic acid
(CH3COOH, both oxygen’s bonded to the second
carbon).
e. State the hybridization of each carbon.
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A 0.0987 M solution of citric acid is prepared.
a. Calculate the pH of the solution. (2.1)
b. Calculate the [OH-] concentration. (1.17 X10-12)
c. Experimentally, the pH is measured to be 2.3.
Using only the pH and the starting molarity
(0.0987 M), calculate Ka. (2.68 X 10-4)
d. Calculate the percent error for Ka. (64%)
e. List the species that would be present in the
solution, indicating the major species.
Acid-Base
Acid-Base
The following questions refer to the weak acid
HF (Ka = 6.8 X 10-4)
a. Calculate the pH and moles of F- in 0.400L of
0.400M HF. (1.8, 6.6 X 10-3 moles)
b. Calculate the percent ionization for the previous
problem. (4.1%)
c. Would the major species be HF or F-?
d. The % ionization of a new fluorine containing
acid (0.200M) is 0.56%. Calculate the Ka (6.3 X
10-6 )
e. Why is HF unique among the binary halogencontaining acids?
Weak Acids
7. What is the percent ionization of a 0.020
M solution of niacin, HC6H4NO2? The
Ka for Niacin is 1.5 X 10-5. (Ans: 2.7%)
8. What is the Ka of HC2H3O2 if a 0.30 M
solution is 0.77% ionized? (Ans: Ka =
1.8 X 10-5)
Acid-Base
pH and Concentration
1. pH depends on
a. Strength of the acid
b. Concentration (molarity)
Show pH from 1 – 14 (Strong, weak and dilute)
2. Example
0.1 M HCl
pH = 1
0.1 M HC2H3O2
pH = 2.8
0.0016 M HCl
pH = 2.8
Weak Acids
% Ionization = [H3O+] X 100
[acid]
6. What is the percent ionization of a 0.10
M solution of HCHO2 ? (Ans: 4.2%)
Acid-Base
Acid Review
Write the eqns for the dissociation of
the following. Indicate all species and
write Ka if needed
HNO3
HNO2
HC7H5O2
HBr
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Acid-Base
NH3 + H2O 
Weak Bases
CH3NH2 + H2O 
1. Do not produce a high concentration of
[OH-] with water
2. Ammonia and Ammonia Derivatives
(Amines)
NH3
(CH3)2NH
CH3NH2
(CH3)3N
C5H5N
Acid-Base
(CH3)2NH + H2O 
(CH3)3N + H2O 
Weak Bases
1. What is the pH of 0.100 M NH3? (Ans:
11.1)
Review
Write the eqns for the dissociation of
the following. Indicate all species and
write Ka or Kb if needed
2. What is the pH of 0.0100 M C5H5N?
(Ans: 8.6)
3. A soln of NH3 has a pH of 10.5. What is
the molarity? (Ans: 0.00587 M)
Acid-Base
Acid-Base
Salts
1. Finding Kb from Ka
HF + H2O 
2. What is Ka for the NH4+ ion? (Ans: 5.6 X
10-10)
Ca(OH)2
HC7H5O2
HCl
C2H5NH2
Acid-Base
Salts of Weak Bases
A. Tend to be positive ions
B. Salts of Weak Bases act as acids
C. Forming Salts
WB
CA
NH3
CH3NH2
C6H5NH2
Salt
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Acid-Base
Salts of Weak Bases
NH4Cl + H2O 
CH3NH3Br + H2O 
C5H5NHNO3 + H2O 
NH4NO3 + H2O 
Acid-Base
Salts of Weak Acids
NaClO + H2O 
NaF + H2O 
Ca(NO2)2 + H2O 
Acid-Base
Salts of Weak Acids
A. Tend to be negative ions
B. Salts of Weak Acids act as bases
C. Forming Salts
WA
CB
HC2H3O2
HC3H5O2
HNO2
HF
Acid-Base
Salt
Salts and pH
1. What is the pH of 0.010 M NaC2H3O2?
(Ans: 8.4)
2. What is the pH of 0.010 M NaF? (Ans:
7.6)
3. What is the pH of 0.010 M NH4Cl?
(Ans: 5.6)
4. What is the pH of 0.010 M (CH3)2NH2Br?
(Ans: 6.4)
5. If the pH of a soln of NaC2H3O2 is 7.4, what is
the concentration? (Ans: 0.00011 M)
Acid-Base
Salts and pH
7. If the pH of C2H5NH3Cl is 6.2, what is
the molarity? (Ans: 0.026 M)
6. If the pH of a soln of C5H5NHNO3 is 3.6, what
is the molarity? (Ans: 0.011 M)
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Acid-Base
Review
Write the eqns for the dissociation of the
following. Indicate all species and write
Ka or Kb if needed
NaOH
HC7H5O2
C2H5NH2
NaC3H5O3
C2H5NH3NO3
HBr
A solution of HClO is tested and the pH is
found to be 4.29
a. Calculate the concentration of HClO in the
solution. (0.0877 M)
b. Would [HClO] or [ClO-] be greater at
equilibrium? Justify your prediction.
c. NaOH is added to the solution of HClO. Write
the reaction that occurs. (Assume the proper
ratios are used).
d. Water is allowed to evaporate from the
solution. What compound is present?
e. Calculate how many grams of NaClO must be
added to make 2.00 L of a solution with a pH
of 10.50. (Ans: 44.7g)
Acid-Base
Acid-Base
Polyprotic Acids
1. Polyprotic Acids – Acids that can
donate more than one H+
2. Important Examples:
H2SO4 - Sulfuric
H3PO4 - Phosphoric
H2CO3 – Carbonic
Polyprotic Acids
1. Write eqns and look up Ka’s for:
H2SO4
H3PO4
2. Much less likely to give away 2nd and
3rd H+ ions
3. H2CO3  HCO3- 
CO32-
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Acid-Base
Acid-Base
Polyprotic Acids
1. Will Na2HPO4 act as an acid or a base in
water: (Identify parent acid)
HPO42- + H2O
Kb=1.6X10-7
HPO42- + H2O
Ka=4.2X10-13
(Use Ka for conj. Acid)
2.
Will K2HC6H5O7 act as an acid or a base in
water?
Acid-Base
Polyprotic Acids
3. Will the following act as acids or bases in
water:
KHS
Na2HAsO4
K3C6H5O7
Na3PO4 (Calculate/estimate pH, 0.100 M)
Acid-Base
Polyprotic Acids
4. What is the pH of 0.0037 M H2CO3?
(Ans: 4.40)
You generally do NOT have to consider the
second or third H+ for the pH
Acid-Base
Carboxylic Acids
A. Carboxyl Group
B. Examples
HCO2H – Formic Acid
HC7H4O2 – Benzoic Acid
HC2H3O2 – Acetic
(CH3CO2H)
(CH3COOH)
Acid-Base
Amino Acids
A. Amino Acid Structure
Amino Acids
Glycine
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Acid-Base
Acid-Base
Amino Acids
B.
C.
D.
E.
20 Amino Acids (8 essential, 10 in children)
Diglycine
Aspartame (Aspartic acid/ Phenylalanine)
Sickle Cell Anemia
-208 AA protein (1 wrong)
-Mutation to help malaria survival rate
-Sickle Cell Red Blood Cell
Acid-Base
Strengths of Binary Acids
• Acidity increases as you go across
– More electronegativity difference
– Bond polarity increase
• Strength increases as you go down
– H-X bond strength decreases with size of X
– X can’t hold H+ as well.
Acid-Base
Acid-Base
Strengths of Oxyacids
• More electronegative pull makes it more acidic
Strengths of Oxyacids
• More oxygens pull on the H’s electrons more.
More acidic.
HClO
Ka = 3.0 X 10-8
HIO
Ka = 2.3 X 10-11
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Hypochlorous
(HClO)
Chlorous
(HClO2)
Chloric
(HClO3)
Perchloric
H – O – Cl
Ka = 3.0 X 10-8
H – O – Cl – O Ka = 1.2 X 10-2
O
H – O – Cl – O Strong Acid
O
H – O – Cl – O Strong Acid
O
Illustrate how two amino acids form a dipeptide. Be sure to
Acid-Base
include the byproduct of the reaction
Why is perchloric acid (HClO4) a strong acid while
hypochlorous acid (HClO) is a weak acid? Draw
structures to support you answer.
Is the oxalate ion, C2O4-2 a weaker or stronger base than
methylamine, CH3NH2? Show all equations and math.
Kb = 1.6 X 10-10 for C2O4-2
vs. Kb = 4.4 X 10-4 for CH3NH2
(HClO4)
Lewis Acids and Bases
Lewis Acid – Electron Pair Acceptor
Lewis Base – Electron Pair Donor
+
Coordination Complexes (transition metals)
Ni2+ + 6NH3  [Ni(NH3)6]2+
Co2+ + 6NH3  [Co(NH3)6]2+
Acid-Base
1. How much more 0.012 M NaOH does it take
to neutralize a solution of HCl that is pH=2
compared to one that is pH 4?
2. Is 0.012 M NaOH an appropriate concentration
to use for both pH values? Suggest any
changes you might want to make.
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Acid-Base
pH = 2
[HCl] = 0.01 M
Pretend 1 L of HCl
Need 833 mL of NaOH
pH = 4
[HCl] = 0.0001 M
Pretend 1 L of HCl
Need 8.33 mL of NaOH
0.012 M is NOT appropriate for pH =4. Use a a
more dilute solution.
Acid-Base
16.Produces OH- and accepts a proton
18.a) C6H5COOPO43b) HCO3C2H5NH3+
20 a) A B
CA CB
b) A B
CB CA
c) B A
CA CB
22. a) H2C6H7O5- + H2O  H3C6H7O5 + OHH2C6H7O5- + H2O  HC6H7O52- + H3O+
b) H3C6H7O5 (CA)
HC6H7O52- (CB)
NH4Cl
Na2CO3
KC2H3O2
KCl
NaH2PO4
32.a) [OH-] = 2.2 X 10-12 (acidic)
b) [OH-] = 6.7 X 10-6 (basic)
c) [OH-] = 3.2 X 10-8 (acidic)
38. a) H+ increases, OH- decreases b) pH = 12.1
c) [H+]=3 X 10-7M, [OH-] = 4 X 10-8M
40.
pH
pOH [H+]
X10-12
11.25
2.75
5.6
7.98
6.02
1.1 X10-8
3.36
10.64 4.4 X10-4
11.93
2.07
3. Which is more acidic: a 0.001 M solution
of HCl or a solution of a weak acid with a
pH of 2.32?
4. The volume of an adult stomach is 450
mL. If the pH is 2.0, how many moles of
H3O+ are present in the stomach. Assume
HCl is the only acid present.
1.2
X10-12
[OH-]
A/B
X10-3
B
9.6 X10-7
B
1.8
42.[H+] from 6 X10-6 to 3 X10-6
[OH-] from 2 X10-9 to 4X10-9
2.3 X10-11 A
8.5 X10-3
B
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44.A) Strong base completely dissociates
b) 0.070 M OHc) False
46. a) 2.87
b) 2.68
c) 2.00
d) 1.90
48. a) 12.91
b) 12.6
c) 10.6
d) 12.1
50.0.0056 M
54.Ka = 5.3 X 10-5
56.2.0 X 10-3
58.2.1 X 10-4 mol HF (1.0 X 10-3 M HF)
60.[HClO] = 9.0 X 10-3 M
62.a) 4.27 b) 5.98 c) 9.51
64.2.59
66.a) 0.721% b) 1.27% c) 2.55 %
74.a) C3H7NH3+ + OHb) H2PO4- + OHc) C6H5CO2H + OH76.[OH-] = 1.5 X 10-3 M pH = 11.17
78.a) Kb = 1.6 X 10-6 b) pKb = 5.79
Ka
KH2AsO4
Kb
1 X 10-7
10-11
1.8 X 10-12
2.3 X 10-8
NaHCO3
5.6 X
NaH2C6H5O7
1.7 X 10-5
1.4 X 10-11
K2CO3
--
1.8 X 10-4
Ca(HC2O4)2
6.4 X 10-5
1.7x10-13
Na2S
---
100,000
LiHC3H2O4
2 X 10-6
6.67 X 10-12
NaHSeO3
5.3 X 10-9
4.3X 10-12
KHS
1 X 10-19
1 X 10-7
KHC4H4O6
4.6 X
80.b) Kb = 1.8 X 10-4 c) CO32- is stronger base
82. a) Ammonia
b) Hydroxylammonium
+
c) Ka NH4 = 5.6 X 10-6, HONH3+ = 9.1X10-7
84.a) pH = 8.09 b) pH = 12.54
94.a) Cl more electronegative than S
b) P is more electronegative than As
c) More O’s
d) Parent acid e) More O’s
96. a) NO3
b) PO43c) CO32-
10-5
1 X 10-11
15