Ch. 19 – Acids & Bases
I. Introduction to
Acids & Bases
Review – Acid Nomenclature
Anion
Ending
Acid Name
-ide
hydro-(stem)-ic acid
-ate
(stem)-ic acid
-ite
(stem)-ous acid
Review – Acid Nomenclature
ACIDS
start with 'H'
2 elements
3 elements
hydro- prefix
-ic ending
no hydro- prefix
-ate ending
becomes
-ic ending
-ite ending
becomes
-ous ending
Review – Naming Acids
 HCl
 H2S
 H2SO4
 H2SO3
 HNO3
 HNO2
 HBr
 Hydrochloric
acid
 Hydrosulfuric acid
 Sulfuric acid
 Sulfurous acid
 Nitric acid
 Nitrous acid
 Hydrobromic acid
A. Properties

electrolytes
 electrolytes

sour taste

bitter taste

turn litmus red

turn litmus blue

react with metals
to form H2 gas

slippery feel

vinegar, milk, soda,
apples, citrus fruits

ammonia, lye,
antacid, baking soda
B. Definitions
– an acid with one H+
 Polyprotic – an acid with more than one H+
• Diprotic – an acid with 2 H+
• Triprotic – an acid with 3 H+
 Monoprotic
HF
monoprotic
H3PO4
triprotic polyprotic
H2SO4
diprotic
B. Definitions
 Arrhenius
• Acids contain hydrogen
• Acids form hydronium ions (H3O+) in
aqueous solution
HCl + H2O 
+
H3O
H
H
Cl
acid
O
H
H
–
+
O
H
+
–
Cl
Cl
H
B. Definitions
 Arrhenius
• Bases contain a hydroxide group
• Bases form hydroxide ions (OH-) in
aqueous solution
H 2O
NaOH 
base
+
Na
+
OH
B. Definitions
 Brønsted-Lowry
• Acids are proton (H+) donors
• Bases are proton (H+) acceptors
HCl + H2O 
acid
–
Cl
+
+
H3O
base
conjugate base
conjugate acid
B. Definitions
 Brønsted-Lowry
• Conjugate Acids are the result after
a base accepts a hydrogen ion
• Conjugate Bases are the result after
an acid donates a hydrogen ion
HBr + NaOH  NaBr + H2O
acid
base
conjugate base
conjugate acid
B. Definitions
H2O + HNO3  H3O+ + NO3–
B
A
CA
CB
H2O + NH3  NH4+ + OHA
B
 Amphoteric
CA
CB
– can be an acid or a base
B. Definitions

Give the conjugate base for each of the following:
-
HF
F
H3PO4
H2PO4
+
H3O
H2O
 Polyprotic
– an acid with more than one H+
B. Definitions

Give the conjugate acid for each of the following:
Br
-
HBr
HSO4
H2SO4
2CO3
HCO3
B. Definitions
 Lewis
• Acids are electron pair acceptors
• Bases are electron pair donors
Lewis
base
Lewis
acid
C. Strength
-
+
 Strong
Acid/Base
• 100% ionized in water
• strong electrolyte
HCl
HNO3
H2SO4
HBr
HI
HClO4
NaOH
KOH
KOH
RbOH
CsOH
Ca(OH)2
Ba(OH)2
C. Strength
 Weak
Acid/Base
• does not ionize completely
• weak electrolyte
HF
CH3COOH
H3PO4
H2CO3
HCN
-
+
NH3
Ch. 19 – Acids & Bases
II. pH
(p. 644 – 658)
A. Ionization of Water
H 2O + H 2 O
H3
+
O
Self-Ionization of Water
+
OH
A. Ionization of Water
Kw = [H3O+][OH-] = 1.0  10-14
Ion Product Constant for Water
• The ion production of water, Kw = [H3O+][OH–]
• Pure water contains equal concentrations of H+
and OH– ions, so [H3O+] = [OH–]
• For all aqueous solutions, the product of the
hydrogen-ion concentration and the hydroxide-ion
concentration equals 1.0 x 10-14
A. Ionization of Water
 Find
the hydroxide ion concentration of
3.0  10-2 M HCl.
HCl
→
H+
+
Cl3.0  10-2M
3.0  10-2M
[H3O+][OH-] = 1.0  10-14
[3.0  10-2][OH-] = 1.0  10-14
[OH-] = 3.3  10-13 M
A. Ionization of Water
 Find
the hydronium ion concentration of
1.4  10-3 M Ca(OH)2.
Ca(OH)2 →
Ca2+
+
2 OH1.4  10-3M
2.8  10-3M
[H3O+][OH-] = 1.0  10-14
[H3O+][2.8  10-3] = 1.0  10-14
[H3O+] = 3.6  10-12 M
B. pH Scale
14
0
7
INCREASING
ACIDITY
NEUTRAL
pH =
INCREASING
BASICITY
+
-log[H3O ]
pouvoir hydrogène (Fr.)
“hydrogen power”
B. pH Scale
pH of Common Substances
B. pH Scale
pH =
+
-log[H3O ]
pOH =
-log[OH ]
pH + pOH = 14
B. pH Scale
 What
is the pH of 0.050 M HNO3?
pH = -log[H3O+]
pH = -log[0.050]
pH = 1.30
Acidic or basic? Acidic
B. pH Scale
 What
is the pH of 0.050 M Ba(OH)2?
[OH-] = 0.100 M
pOH = -log[OH-]
pOH = -log[0.100]
pOH = 1.00
pH = 13.00
Acidic or basic?
Basic
B. pH Scale
 What
is the molarity of HBr in a solution
that has a pOH of 9.60?
pH + pOH = 14
pH = -log[H3O+]
pH + 9.60 = 14
4.40 = -log[H3O+]
pH = 4.40
-4.40 = log[H3O+]
Acidic
[H3O+] = 4.0  10-5 M HBr
C. pH Worksheet #6
A swimming pool has a volume of one million liters. How many grams of HCl
would need to be added to that swimming pool to bring the pH down from
7.0000 to 4.0000? (Assume the volume of the HCl is negligible)
7 = -log[H+]
-7 = log[H+]
[H+] = 1 x 10-7 M
-4 = log[H+]
[H+] = 1 x 10-4 M
1,000,000L
Sol’n
1x10-7
mol H+
1L
soln
1,000,000L
Sol’n
1x10-4
mol H+
1L
soln
= 0.1 mol
H+
= 100 mol
H+
C. pH Worksheet #6
A swimming pool has a volume of one million liters. How many grams of
HCl would need to be added to that swimming pool to bring the pH down
from 7.0000 to 4.0000? (Assume the volume of the HCl is negligible)
100 mol H+ – 0.1 mol H+
= 99.9 mol HCl
99.9 mol
HCl
36.46 g HCl
1 mol
HCl
= 3642 g HCl
D. pH Sig Figs
 For
the pH, the number of sig figs is
shown by the # of decimal places
• [H+] = 2.26 x 10-4 M => pH = 3.646
 For the molarity from the pH, check
decimal places in the pH
• pH = 4.25 => 5.6 x 10-5 M