Acids, Bases, and Salts

1
Acids, Bases, and Salts
Preparation for College Chemistry Columbia
University Department of Chemistry
2
Chapter Outline
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Acids and Bases Definitions
Base
Theory
Acid
H-containing, releases H in water
Arrhenius 1884
OH-containing, releases OH - in water
Brönsted-Lowry 1923
Proton (H ) acceptor
Proton (H ) donor
Electron-pair donor
Electron-pair acceptor
Lewis 1930s
4
Acid-Base Conjugate Pair
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Acidity Constant, Ka
strong acid
strong base
weak base
weak acid
H3O(aq) Cl -(aq)
HCl (aq) H2O
weak base
strong acid
6
Basicity Constant, Kb
strong acid
strong base
weak base
weak acid
Na (aq) OH -(aq)
NaOH (aq) H2O
weak acid
strong base
7
Ka and Kb values
Acid
Base
Ka
Kb
HCHO2
Mg(OH)2
1.8x 10 -4
1.0x 10 -1
HCNO
NH3
5.6x 10 -4
2.0x 10 -4
HF
Be(OH)2
5.6x 10 -5
6.5x 10 -4
HNO2
1.1x 10 -6
N2H2
4.5x 10 -4
HC2H3O2
Strength
1.8x 10 -5
1.9x 10 -8
Al(OH)3
Strength
HC6H5O2
NH2OH
1.3x 10 -10
1.x 10 -8
PH3
HCN
4.0x 10 -10
1.x 10 -28
8
p-function -log fx
x -1
9
pH Scale
H (mol/L)
H (mol/L)
pH
pH
Neutral
1x 10 -7
14
7
1x 10 -14
Basicity
1x 10 -13
1x 10 -6
6
13
12
5
1x 10 -12
1x 10 -5
1x 10 -4
1x 10 -11
4
11
1x 10 -3
10
3
1x 10 -10
Acidity
1x 10 -2
9
2
1x 10 -9
8
1x 10 -8
1x 10 -1
1
10
Hydrolysis
Base
Acid
Salt pH
Strong
Strong
Neutral
Strong
Weak
Basic
Weak
Strong
Acidic
Weak
Weak
Depends on Ka and Kb
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Neutralization Reactions
Writing the ionic equation and eliminating
SPECTATOR IONS
Net ionic equation
Net ionic equation
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Buffer Solutions
Resist changes in pH when small amounts of
diluted acids and bases are added.
Weak acid mixed with its conjugate base
Two types
Weak base mixed with its conjugate acid
13
Henderson-Hasselbalch Equation
Applying p function
or
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Replaceable Hydrogens
Monoprotic Acids
HCl, HC2H3O2 , HNO3 , HC9H19O2
H2SO4 , H2C2O2 , H2C2O2
Diprotic Acids
Polyprotic Acids
H3PO4
The Carboxylic Functional Group
OH
C
O
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Titration curves
Strong Acid - Strong Base
Strong Base - Strong Acid
Strong Acid - Weak Base
Strong Base - Weak Acid