Chapter 19: Acids And Bases
Class question
• Where can acids
be found?
–
–
–
–
Sodas
Stomach
Vinegar
Citrus fruits
• Where can bases
be found?
–
–
–
–
–
Soap
Drano
Antacid tablets
Windex
detergent
Properties of Acids
• Taste sour
• React with bases
• Litmus paper test – turn blue litmus
paper red
• Electrolytic – conduct electricity
Properties of Bases
•
•
•
•
Taste bitter
Feels slippery
React with acids
Litmus paper test – turn red litmus
paper blue
• electrolytic
Nomenclature of Acids
• Acids are composed of a(n)
Hydrogen ion (H+)
________________ followed by
anion
a(n)
_______
Ex:
H+ + Cl1H+ + SO42-
HCl
H2SO4
H+ + anion
• H+ + anion with –ide ending 
Hydro _____ic acid
acid name is __________________
HCl
chloride
anion? _______
Hydrochloric
acid
acid name ________________
H+ + anion
• H+ + anion with –ide ending 
Hydro _____ic acid
acid name is __________________
HF
fluoride
anion? _______
Hydrofluoric
acid
acid name ________________
H+ + anion
• H+ + anion with –ate ending 
_____ic acid
acid name is __________________
HNO3
nitrate
anion? _______
nitric
acid
acid name ________________
H+ + anion
• H+ + anion with –ate ending 
_____ic acid
acid name is __________________
H2SO4
sulfate
anion? _______
sulfuric
acid
acid name ________________
H+ + anion
• H+ + anion with –ite ending 
_____ous acid
acid name is __________________
HNO2
nitrite
anion? _______
nitrous
acid
acid name ________________
H+ + anion
• H+ + anion with –ite ending 
_____ous acid
acid name is __________________
HClO2
chlorite
anion? _______
chlorous
acid
acid name ________________
Writing acid formulas
• Hydrobromic acid
1-)
HBr
Bromide
(Br
anion? ___________ formula ______
• Acetic acid
1-)
HC
H
O
acetate(C
H
O
2
3
2
3
2
anion? ___________ formula ______ 2
• Nitrous acid
1-)
HNO
nitrite
(NO
2
2
anion? ___________ formula ______
Nomenclature of Bases
• Bases are composed of a(n)
cation followed by
_______
hydroxide (OH1-)
a(n) ________________
Writing Base Names
• Rule: name the cation and add
“hydroxide”
• NaOH
• Mg(OH)2
• Fe(OH)3
sodium hydroxide
magnesium hydroxide
Iron (III) hydroxide
Memorize: NH3 = ammonia
Writing base formulas
• potassium hydroxide
+
KOH
K
cation? ______ formula ______
• Calcium hydroxide
2+
Ca(OH)
Ca
cation? ______ formula ______ 2
• Aluminum hydroxide
Al(OH)
3+
Al
cation? ______ formula ______ 3
Ions In Solution
• Why are some solutions acidic, basic,
or neutral?
depends on number of H+ and OHions present
Ions In Solution
• Acidic solution – contain more H+ ions
than OH- ions
4000 H+ and 0 OH- is acidic
1000 H+ and 500 OH- is acidic
5 H+ and 3 OH- is acidic
Ions In Solution
• Basic Solution – contain more OHions than H+ ions
4000 OH- and 0 H+ is basic
1000 OH- and 500 H+ is basic
5 OH- and 3 H+ is basic
Ions In Solution
• Neutral Solution – equal amounts of
H+ and OH- ions
4000 OH- and 4000 H+ is neutral
1000 OH- and 1000 H+ is neutral
5 OH- and 5 H+ is neutral
Self Ionization of Water
• simplified version
H2 O
H
+
+ OH-
Types of Acids/Bases
• Arrhenius Model
• Bronsted-Lowry Model
Arrhenius Model of
Acids and Bases
• Arrhenius Acids
– Defn: contain H+ and ionizes to form H+
– Examples
+ + ClH
HCl 
+ + NO H
3
HNO3 
makes
solution
ACIDIC
Arrhenius Model of
Acids and Bases
• Arrhenius Bases
– Defn:
– contain OH- and ionizes to produce OH- ions
makes
– Examples
solution
NaOH 
Na+ + OH-
Ca(OH)2 
Ca2+ + 2 OH-
BASIC
Bronsted-Lowry Model
• Bronsted-Lowry Acid
– Defn: proton/H+ donor
• can give H+ to another species
• Bronsted-Lowry Base
– Defn: proton/H+ acceptor
• can take H+ from another species
Bronsted-Lowry Model
• REMEMBER!!!! REMEMBER!!!!
acids donate, bases accept protons
Ashley does boys always
Bronsted-Lowry Model
• Examples
HCl + H2O  Cl- + H3O+
Acid
Base
(donates (accepts
proton) proton)
What is
happening
here?
Which is the
acid? base?
Bronsted-Lowry Model
• Examples
NH3 + H2O  NH4+ +
Base
(accepts
proton)
Acid
(donates
proton)
What is
happening
OH here?
Which is the
acid? base?
Conjugate Acid/Base Pairs
• Conjugate acid – new species
produced when base gains H+ ion
• Conjugate base – new species
produced when acid donates H+ ion
Conjugate Acid/Base
Pairs
• general Bronsted-Lowry reaction
conj. acid/base pair
acid + base  conj. acid + conj. base
conj. acid/base pair
Every acid has a conjugate base.
Every base has a conjugate acid.
Conjugate Acid/Base
Pairs
• Examples
conj. acid/base pair
HNO3 + H2O  H3O+ + NO3acid
base
C.A.
conj. acid/base pair
C.B.
What is
the acid?
base?
What is
the
conjugate
acid/base?
Conjugate Acid/Base
Pairs
• Examples
conj. acid/base pair
NH3 + H2O  NH4+ + OHbase
acid
C.A.
conj. acid/base pair
C.B.
What is
the acid?
base?
What is
the
conjugate
acid/base?
Conjugate acid-base
pairs
• What is the conjugate base of:
1HSO
H2O
4
H2SO4 _________
H3O+ ________
• What is the conjugate acid of:
1H
PO
H2O
22
4
HPO4 _________
OH1- ________
How can H2O be both acid and base?
Amphoteric
• Defn – substance that can act as
both acids and bases
HNO3 + H2O  H3O+ + NO3base
NH3 + H2O  NH4+ + OHacid
Is H2O a
base or acid?
Is H2O a
base or acid?
Water is amphoteric b/c it is acts as a
base in one reaction and acts as an acid
in the second
Mono-, Di-, Triprotic Acids
• Defns
– monoprotic (HA) – one ionizable proton
ex: HF, HCl, HBr
– diprotic (H2A) – two ionizable protons
ex: H2SO4, H2CO3
– triprotic (H3A) – three ionizable protons
ex: H3PO4, H3BO3
Polyprotic Acid
Ionization
• Always forms ONE H+
H3PO4 
H2PO41- + H+
H2PO41- 
HPO42- + H+
HPO42- 
PO43- + H+
Strong Acid/Base
• Defn – acid or base that completely
ionizes
HA
XOH
100%
ionization
100%
ionization
H+ + AX+ + OH-
every single HA molecule ionizes into
H+ and A-
Strong Acid
• Illustration
H
H
H
A
A
A
+
+
+
+
-
+
-
+
-
All break into ions
6 Strong Acids
•
•
•
•
•
•
HCl – hydrochloric acid
HBr – hydrobromic acid
HI – hydroiodic acid
HClO4 – perchloric acid
H2SO4 – sulfuric acid
HNO3 – nitric acid
Strong Bases
• Group I and II metal hydroxides
LiOH
Mg(OH)2
NaOH
Ca(OH)2
KOH
Sr(OH)2
RbOH
Ba(OH)2
No need to
memorize
exact ones
Weak Acid/Base
• Defn – acid or base that partially
ionizes
HA
XOH
partial
ionization
H+ + AX+ + OH-
not all will ionize; the weaker it is
the less it ionizes
Weak Acid
• Illustration
H
A
H
A
H
A
+
+
Only some break into ions
-
What are the weak acids
and bases?
• The ones that are NOT strong
Strong or weak,
concentrated or diluted
• For acids and bases, it is important
to distinguish between concentrated
and dilute from strong and weak. The
strong
concentrated
words _________
and __________
have different meanings. Similarly,
weak
dilute
___________
and ___________
are not the same either.
Strong or weak,
concentrated or diluted
• Strong and weak refer to
how much substance ionizes
____________________________
• Concentrated and dilute refer to
how much solute is present
____________________________
Example
• 1 M HCl
Strong and dilute
• 12 M HCl
Strong and concentrated
• 1 M H2CO3
weak and dilute
• 12 M H2CO3
weak and concentrated
Ion Product Constant for
Water (Kw)
• Defn: equilibrium value for self
ionization of water (H2O  H+ + OH-)
• Formula
Kw = [H+][OH-] = 1 x 10-14
ALWAYS
ALWAYS
ALWAYS
Is solution acidic, basic,
or neutral?
• Acidic
[H+] > [OH-]
• Basic
[H+] < [OH-]
• neutral
[H+] = [OH-]
pH and pOH
•
pH
a) Defn: pH = -log [H+]
b) Scale: range from 0 to 14
ACIDIC
pH
0
BASIC
7
(neutral)
14
pH
c) change one pH unit 
represents a ten fold change in
strength
- ex: pH = 3 vs pH = 4
pH 3 is 101 or 10 times more acidic
- ex: pH = 7 vs pH = 10
pH 7 is 103 or 1000 times more acidic
pOH
• Formula: -log [OH-]
Relation of pH and pOH
• pH + pOH = 14
If given one variable, subtract to find the other
Overall Relationship
pH
pOH
[H+]
[OH-]
Sample problem (a)
• Calculate the pH of a solution with
[H+] = 3.0 x 10-6 M.
pH = -log [H+]
= - log [3.0 x 10-6]
= 5.52
Sample problem (b)
• Calculate the pH of a solution with
[OH-] = 8.2 x 10-6.
pOH = -log[OH-]
= -log [8.2 x 10-6]
= 5.09
Sample problem (b)
pH + pOH = 14
pH + 5.09 = 14
pH = 8.91
Sample problem (c)
• What is the [H+] of a solution with
pH = 2?
pH = -log[H+]
[H+] = 10-pH
= 10-2
= 0.01 M
Sample problem (d)
• (i) What is the [OH-] of a solution
with pOH = 3.7?
[OH-] = 10-pOH
[OH-] = 10-3.7
= 2 x 10-4 M
Sample problem (d)
• (ii) What is the pH?
pH + pOH = 14
pH + 3.7 = 14
pH = 10.3
Sample problem (d)
• (iii) What is the [H+] ?
[H+] = 10-pH
= 10-10.3
= 5 x 10-11 M
Reaction between acids
and bases
• Neutralization (defn) – reaction of
acid and base to form a salt and
water
– The reaction is a double replacement
• Salt (defn) – ionic compound made of
cation from base and anion from
acid
Reaction between acids
and bases
• Ex reaction
Mg(OH)2 + HCl 
base
Mg2+ + OH-
acid
H+ + Cl-
MgCl2 + H2O
salt
water
Mg2+ - cation from base
Cl- - anion from acid
Ex problems
• i) What is the salt formed from
sulfuric acid (H2SO4) and
potassium hydroxide (KOH)?
base cation? K+
2SO
acid anion?
4
What is salt?
K2SO4
Ex problems
• ii) What is the salt formed when
Al(OH)3 and HBr react?
base cation?
acid anion?
Al3+
Br-
What is salt? AlBr3
Salt Hydrolysis
• Basically says – what is the acid and
base that formed the salt solution?
What is the parent acid? H+ and salt anion
What is the parent base? Salt cation and OH-
Ex problems
• What is parent acid and base of
these salts?
What ions
+
a) NaCl  Na + Cl
make up NaCl?
Acid?
Base?
H+ + Cl- 
Na+ + OH- 
HCl
NaOH
Ex problems
• What is parent acid and base of
these salts?
What ions make
+
3b) K3PO4  K + PO4
up K PO ?
3
Acid?
Base?
H+ + PO43-  H3PO4
KOH
K+ + OH- 
4
Is salt solution acidic,
basic, or neutral?
• a) strong acid + strong base 
Neutral salt
• b) strong acid + weak base 
acidic salt
• c) weak acid + strong base 
basic salt
Ex problem
•
Determine if salt solution is acidic,
basic, or neutral.
a) LiBr  Li+ + Bracid? HBr (strong acid)
base? LiOH (strong base)
NEUTRAL
Salt is ____________
Ex problem
•
Determine if salt solution is acidic,
basic, or neutral.
b) Fe(NO3)3  Fe3+ + NO3(strong acid)
acid? HNO3
base? Fe(OH)3 (weak base)
ACIDIC
Salt is ____________