Ch#14 Acids and Bases

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Chapter #14
Acids, Bases, and Salts
Acids, Bases and Salts Topics
The Arrhenius Theory
The Brønsted Theory
Naming Acids (See Nomenclature Notes)
The Self-Ionization of Water
The pH Concept
Properties of Acids
Properties of Bases
Salts
The Strengths of Acids and Bases
Analyzing Acids and Bases
Titration Calculations
Hydrolysis Reactions of Salts
Buffers
History of Acids and Bases
In the early days of chemistry chemists were organizing
physical and chemical properties of substances. They
discovered that many substances could be placed in two
different property categories:
Substance B
Substance A
1.
Bitter taste
1.
Sour taste
2.
Reacts with carbonates to make CO2 2.
3.
Reacts with metals to produce H2
3.
Do not react with metals
4.
Turns blue litmus pink
4.
Turns red litmus blue
5.
Reacts with B substances to make
salt water
5.
Reacts with A substances make
salt and water
Reacts with fats to make soaps
Arrhenius was the first person to suggest a reason why
substances are in A or B due to their ionization in water.
Arrhenius Theory
The Swedish chemist Svante Arrhenius proposed the first
definition of acids and bases.
(Substances A and B became
known as acids and bases)
According to the Arrhenius model:
“acids are substances that dissociate in water to
produce H+ ions and bases are substances that
dissociate in water to produce OH- ions”
NaOH (aq)  Na+ (aq) + OH- (aq)
Base
HCl (aq)  H+ (aq) + Cl- (aq)
Acid
What is
+
H?
e-
+
Hydrogen (H)
+
Proton (H+)
Hydronium Ion
Unknown to Arrhenius free H+ ions do not exist in water. They
covalently react with water to produce hydronium ions, H3O+.
or:
H+ (aq) + H2O (l)  H3O+ (aq)
This new bond is called a coordinate covalent bond since
both new bonding electrons come from the same atom
Hydronium Ion
Hydronium ion is the name for H3O+ and is often times
abbreviated as H+ (aq) they both mean the same thing.
What is the difference between a strong acid and a weak
acid?
Hydronium Ion
Hydronium ion is the name for H3O+ and is often times
abbreviated as H+ (aq) they both mean the same thing.
What is the difference between a strong acid and a weak
acid? Strong acids ionize 100% and weak ones do not!
Hydronium Ion
Hydronium ion is the name for H3O+ and is often times
abbreviated as H+ (aq) they both mean the same thing.
What is the difference between a strong acid and a weak
acid? Strong acids ionize 100% and weak ones do not!
A single arrow is used to represent the ionization of a strong
acid. Double arrows (Equilibrium) are used to represent
weak acids.
For example:
HCl (g)
H+ (aq) + Cl - (aq)
HF (g)
H+ (aq) + F -
Hydronium Ion
Hydronium ion is the name for H3O+ and is often times
abbreviated as H+ (aq) they both mean the same thing.
What is the difference between a strong acid and a weak
acid? Strong acids ionize 100% and weak ones do not!
A single arrow is used to represent the ionization of a strong
acid. Double arrows (Equilibrium) are used to represent
weak acids.
For example:
HCl (g)
H+ (aq) + Cl - (aq)
HF (g)
H+ (aq) + F -
According to Arrhenius, is water an acid or base?
HOH (l)
H+ (aq) + OH –
(aq)
Hydronium Ion
Hydronium ion is the name for H3O+ and is often times
abbreviated as H+ (aq) they both mean the same thing.
What is the difference between a strong acid and a weak
acid? Strong acids ionize 100% and weak ones do not!
A single arrow is used to represent the ionization of a strong
acid. Double arrows (Equilibrium) are used to represent
weak acids.
For example:
HCl (g)
H+ (aq) + Cl - (aq)
HF (g)
H+ (aq) + F -
According to Arrhenius, is water an acid or base?
HOH (l)
H+ (aq) + OH –
(aq)
Neither, he called it Neutral (same amount of OH- and H+
Strong Acids and Bases
How can we identify strong acids or bases?
Strong Acids and Bases
How can we identify strong acids or bases?
Easy memorize them!
Strong Acids and Bases
How can we identify strong acids or bases?
Easy, memorize them!
Memorized Strong Acids
1. HClO4
2. H2SO4
3. HI
4. HBr
5. HCl
6. HNO3
Memorized Strong Bases
Hydroxides of group 1 and 2
metals, excluding Be and Mg
Bronsted Lowry Theory
Johannes Brønsted and Thomas Lowry revised
Arrhenius’s acid-base theory to include this behavior.
They defined acids and bases as follows:
Bronsted
Lowry
“An acid is a hydrogen containing species that
donates a proton. A base is any substance that
accepts a proton”
HCl (aq) + H2O (l)  Cl- (aq) + H3O+ (aq)
In the above example what is the Brønsted acid? What is
the Brønsted base?
Bronsted Lowry Theory
In reality, the reaction of HCl with H2O is an equilibrium
and occurs in both directions, although in this case the
equilibrium lies far to the right.
HCl (aq) + H2O (l)  Cl - ( aq) + H3O+ (aq)
For the reverse reaction Cl - behaves as a Brønsted
base and H3O+ behaves as a Brønsted acid.
The Cl- is called the conjugate base of HCl. Brønsted
acids and bases always exist as conjugate acid-base
pairs.
Autoionization of Water
In pure water (no solute) water molecules behave as both an
acid and base!!
e.g.
H2O (l) + H2O (l)  H3O+ (aq) + OH- (aq)
This is called the self-ionization (autoionizaion) of water.
Although the equilibrium lies far to the left it is very important to
take into consideration, especially for living systems.
Does anyone know how we write the equilibrium constant for
this reaction?
Autoionization of Water
The auto-ionization of water is described by the
equation:
H2O (l) + H2O (l)  H3O+ (aq) + OH- (aq)
The equilibrium constant for this reaction is given by:
[H3O ][OH ] [H3O ][OH ]
K

[H2O][H2O]
[H2O]2
K[H2O]2  [H3O ][OH ]
Kw = K[H2O]2 = 10-14 This equilibrium lies very much
to the left i.e. mostly water. For pure water [OH-] =
[H+] = 1 x 10-7 M
Autoionization of Water
As [OH-] and [H+] are so small the [H2O] is not affected by their
formation. It is useful to define a new constant Kw such that:
1.00 g
ml
mole
18.0 g
ml
10-3 L
=
55.5 M
[H3O ][OH ] [H3O ][OH ]
K

[H2O][H2O]
[H2O]2
K[H2O]2  K w  [H3O ][OH ]
Kw is called the ion product of water.
What is the value for the ion product of water?
Autoionization of Water
As [OH-] and [H+] are so small the [H2O] is not affected by their
formation. It is useful to define a new constant Kw such that:
1.00 g
ml
mole
18.0 g
ml
10-3 L
=
55.5 M
[H3O ][OH ] [H3O ][OH ]
K

[H2O][H2O]
[H2O]2
K[H2O]2  K w  [H3O ][OH ]
Kw is called the ion product of water.
What is the value for the ion product of water?
[H+][OH-] = 10-14
Autoionization of Water
We define an aqueous solution as being neutral when the
[H+] = [OH-].
We define an aqueous solution as being acidic when
[H+] > [OH-].
We define an aqueous solution as being basic when
[H+] < [OH-].
However, in each case Kw = 1 x 10-14 M2
[H+] = 0.0000001 = 10-7 (how can this be abbreviated further?)
Autoionization of Water
We define an aqueous solution as being neutral when the
[H+] = [OH-].
We define an aqueous solution as being acidic when
[H+] > [OH-].
We define an aqueous solution as being basic when
[H+] < [OH-].
However, in each case Kw = 1 x 10-14 M2
[H+] = 0.0000001 = 10-7 (how can this be abbreviated further?)
By just describing the power
Autoionization of Water
We define an aqueous solution as being neutral when the
[H+] = [OH-].
We define an aqueous solution as being acidic when
[H+] > [OH-].
We define an aqueous solution as being basic when
[H+] < [OH-].
However, in each case Kw = 1 x 10-14 M2
[H+] = 0.0000001 = 10-7 (how can this be abbreviated further?)
By just describing the power Called the power of H, or pH.
Autoionization of Water
We define an aqueous solution as being neutral when the
[H+] = [OH-].
We define an aqueous solution as being acidic when
[H+] > [OH-].
We define an aqueous solution as being basic when
[H+] < [OH-].
However, in each case Kw = 1 x 10-14 M2
[H+] = 0.0000001 = 10-7 (how can this be abbreviated further?)
By just describing the power Called the power of H, or pH.
Our math departments tells us that log means
pH = 7 power too.
The mathematical definition of pH using [H+] for [H3O+] is
listed below:
pH = -log [H+], or [H+]= 1x10-pH (both are mathematically
equivalent)
How about the power for the OH -, what should this be
called?
Autoionization of Water
The mathematical definition of pH using [H+] for [H3O+] is listed
below:
pH = -log [H+], or [H+] = 1x10-pH (both are mathematically
equivalent)
How about the power for the OH -, what should this be called?
Would you believe pOH?
Autoionization of Water
The mathematical definition of pH using [H+] for [H3O+] is
listed below:
pH = -log [H+], or [H+]= 1x10-pH (both are mathematically
equivalent)
How about the power for the OH -, what should this be
called? Would you believe pOH?
Have you heard of pOH before?
Autoionization of Water
The mathematical definition of pH using [H+] for [H3O+] is
listed below:
pH = -log [H+], or [H+]= 1x10-pH (both are mathematically
equivalent)
How about the power for the OH -, what should this be
called? Would you believe pOH?
Have you heard of pOH before?
pH + pOH = 14 for water solutions.
Now for some examples
1. Find the pH and pOH, when [H+] = 10-4
Now for some examples
1. Find the pH and pOH, when [H+] = 10-4
pH = 4 and pOH = 10, since they must add to 14
using the calculator pH = -log [H+], type in 10-4, push
the log button and pH = -(-4) = 4. Same for pOH
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
pH = 16
pH = 12
pH = 7
[H+] = 10-2
pH = 2
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
pH = 16
pH = 12
pH = 7
pH = 2
[H+] = 10-2
[OH -] = 10-12
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
pH = 16
pH = 12
pH = 7
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
pH = 16
pH = 12
pH = 7
[H+] = 10-7
[OH -] = 10-7
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
pH = 16
pH = 12
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
pH = 16
pH = 12
[H+] =10-12
[OH -] = 10-2
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
pH = 16
pH = 12
[H+] =10-12
[OH -] = 10-2
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
[H+] < [OH -]
basic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
[H+] =10-16
pH = 16
[OH -] =
pH = 12
[H+] =10-12
[OH -] = 10-2
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
[H+] < [OH -]
basic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
[H+] =10-16
pH = 16
[OH -] = 102
pH = 12
[H+] =10-12
[OH -] = 10-2
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
[H+] < [OH -]
basic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
[H+] =10-1
pH = 16
[OH -] = 102
[H+] < [OH -]
basic
pH = 12
[H+] =10-12
[OH -] = 10-2
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
[H+] < [OH -]
basic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
[H+] =10-16
pH = 16
[OH -] = 102
[H+] < [OH -]
basic
pH = 12
[H+] =10-12
[OH -] = 10-2
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
acidic
[H+] < [OH -]
basic
A pH Number line
Number lines have been used in history and math classes,
so to keep up we use them in chemistry classes.
[H+] =10-16
pH = 16
[OH -] = 102
basic
[H+] < [OH -]
basic
pH = 12
[H+] =10-12
[OH -] = 10-2
pH = 7
[H+] = 10-7
[OH -] = 10-7
[H+] = [OH -]
neutral
pH = 2
[H+] = 10-2
[OH -] = 10-12
[H+] > [OH -]
acidic
acidic
[H+] < [OH -]
basic
Equations With Acuids
Acids undergo characteristic double replacement reactions
with oxides, hydroxides, carbonates and bicarbonates.
e.g.
2HCl (aq) + CuO (s)  CuCl2 (aq) + H2O (l)
2HCl (aq) + Ca(OH)2 (aq)  CaCl2 (aq) + 2H2O (l)
2HCl (aq) + CaCO3 (aq)  CaCl2 (aq) + H2O (l) + CO2 (g)
2HC l (aq) + Sr(HCO3)2 (aq)  SrCl2 (aq) + 2H2O (l) + 2CO2 (g)
Equations With Acuids
Bases undergo a double replacement reaction with acids
called neutralization:
NaOH (aq) + HCl (aq)  H2O (l) + NaC l (aq)
In words this well known reaction is often described as:
“acid plus base = salt plus water”
We previously discussed this reaction when describing types of
reactions.
Ionic Equations (a review)
We have discussed the double replacement reactions and ionic
equations before. Since the acids and bases undergo double
replacement reactions called neutralization reactions, then they
can have ionic equations too.
e.g.
Formula equation:
HCl (aq) + NaOH (aq)  NaCl (aq) + H2O (l)
Ionic equation:
H+ (aq) + Cl- (aq) + Na+ (aq) + OH- (aq)  Na+ (aq) + Cl- (aq) + H2O (l)
Net ionic equation:
H+ (aq) + OH- (aq)  H2O (l)
Acidic Single Replacement Reactions
Another property of acids is their reaction with certain metals to
produce hydrogen gas, H2 (g).
Zn (s) + 2HC l (aq)  H2 (g) + ZnCl2 (aq)
This is an example of a single replacement reaction and is a
redox reaction.
Total ionic equation:
Zn (s) + 2H+ (aq) + 2Cl- (aq)  H2 (g) + Zn2+ (aq) + 2Cl- (aq)
Net ionic equation:
Zn (s) + 2H+ (aq)  H2 (g) + Zn2+ (aq)
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
2. NaC2H3O2
3. NH4Cl
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
1. NaC2H3O2
1. NH4Cl
Reactants are?
NaCl + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
2. NaC2H3O2
3. NH4Cl
HCl + NaOH
s.b.
S.A.
NaCl + HOH
NaC2H3O2 + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
Neutral salt
2. NaC2H3O2
3. NH4Cl
HCl + NaOH
s.b.
S.A.
NaCl + HOH
NaC2H3O2 + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
Neutral salt
2. NaC2H3O2
3. NH4Cl
HCl + NaOH
s.a.
s.b.
HC2H3O2 + NaOH
NaCl + HOH
NaC2H3O2 + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
HCl + NaOH
s.a.
Neutral salt
2. NaC2H3O2
HC2H3O2 + NaOH
w.a.
3. NH4Cl
s.b.
s.b.
NaCl + HOH
NaC2H3O2 + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
HCl + NaOH
s.a.
Neutral salt
2. NaC2H3O2
basic salt
3. NH4Cl
s.b.
HC2H3O2 + NaOH
w.a.
s.b.
NaCl + HOH
NaC2H3O2 + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
HCl + NaOH
s.a.
Neutral salt
2. NaC2H3O2
basic salt
3. NH4Cl
s.b.
HC2H3O2 + NaOH
w.a.
NaCl + HOH
NaC2H3O2 + HOH
s.b.
NH4Cl + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
HCl + NaOH
s.a.
Neutral salt
2. NaC2H3O2
basic salt
3. NH4Cl
s.b.
HC2H3O2 + NaOH
w.a.
NaCl + HOH
NaC2H3O2 + HOH
s.b.
HCl + NH4OH
NH4Cl + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
HCl + NaOH
s.a.
Neutral salt
2. NaC2H3O2
basic salt
3. NH4Cl
s.b.
HC2H3O2 + NaOH
w.a.
NaC2H3O2 + HOH
s.b.
HCl + NH4OH
s.a.
NaCl + HOH
w.b.
NH4Cl + HOH
Salts
Salts are the ionic product of an acid base neutralization
reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from
and label the salts as acidic, basic, or neutral.
1. NaCl
HCl + NaOH
s.a.
neutral salt
2. NaC2H3O2
basic salt
3. NH4Cl
acidic salt
s.b.
HC2H3O2 + NaOH
w.a.
NaC2H3O2 + HOH
s.b.
HCl + NH4OH
s.a.
NaCl + HOH
w.b.
NH4Cl + HOH
Acid, Base, and Salt Hydrolysis
HBr (aq)
Acid, Base, and Salt Hydrolysis
HBr (aq)
H+ (aq)
+
Br
- (aq)
Acid, Base, and Salt Hydrolysis
HBr (aq)
H+ (aq)
+
Br
- (aq)
Acidic, because H+ (aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
Initial concentration
H+ (aq)
+
Br
- (aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
Initial concentration
0.0
H+ (aq)
+
Br
- (aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
H+ (aq)
Initial concentration
?
+
Br
- (aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
H+ (aq)
Initial concentration
0.0
+
Br
- (aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
?
Initial concentration
H+ (aq)
+
Br
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Initial concentration
H+ (aq)
?
+
Br
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Initial concentration
H+ (aq)
0.1
+
Br
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Initial concentration
H+ (aq)
0.1
+
Br
?
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
[H+] = ?
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
[H+] = 0.1
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
[H+] = 0.1
pH = ?
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
[H+] = 0.1 = 10-1
pH = ?
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
[H+] = 0.1 = 10-1
pH = 1
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
pH = 1
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
+
Br
0.1
- (aq)
pH = 1
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
+
Br
- (aq)
0.1
Ca2+ (aq) + 2 OH-
pH = 1
Final concentration
(aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
+
Br
- (aq)
0.1
Ca2+ (aq) + 2 OH-
pH = 1
Final concentration
(aq)
acidic?
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
+
Br
- (aq)
0.1
Ca2+ (aq) + 2 OH-
pH = 1
Final concentration
(aq)
No, basic OH-
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Initial concentration
H+ (aq)
0.1
+
Br
- (aq)
0.1
0.1
Ca(OH)2 (aq)
Ca2+ (aq) + 2 OH-
pH = 1
Final concentration
Initial concentration
(aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
0.0
+
Br
- (aq)
0.1
Ca2+ (aq) + 2 OH-
pH = 1
Final concentration
Initial concentration
(aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
0.0
+
Br
- (aq)
0.1
pH = 1
Final concentration
?
Ca2+ (aq) + 2 OH-
Initial concentration
(aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
Initial concentration
H+ (aq)
0.1
0.0
+
Br
- (aq)
0.1
pH = 1
Final concentration
0.0
Ca2+ (aq) + 2 OH-
Initial concentration
(aq)
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
?
Initial concentration
H+ (aq)
0.1
0.0
+
Br
- (aq)
0.1
pH = 1
Final concentration
0.0
Ca2+ (aq) + 2 OH-
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH?
pH = 1
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
?
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
[OH - ] = ?
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
[OH - ] = 0.2
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
[OH - ] = 0.2
pOH = ?
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
Initial concentration
H+ (aq)
Ca(OH)2 (aq)
Br
- (aq)
0.1
0.1
0.1
+
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH-
0.0
[OH - ] = 0.2
pOH = - log[OH-]
0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
[OH - ] = 0.2
pOH = - log[OH-] = - log[0.2]
pH = 1
0.2
Initial concentration
(aq)
Final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
[OH - ] = 0.2
pOH = - log[OH-] = - log[0.2] = -(-0.698970004)
pOH = 0.7
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
[OH - ] = 0.2
pOH = - log[OH-] = - log[0.2] = -(-0.698970004)
pOH = 0.7
pH = ?
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
Final concentration
[OH - ] = 0.2
pOH = - log[OH-] = - log[0.2] = -(-0.698970004)
pOH = 0.7
pH = 14.0 - 0.07 = 13.3
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
pH = 13.3
final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
NaF (aq)
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Initial concentration
(aq)
pH = 13.3
final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
NaF (aq)
Initial concentration
H+ (aq)
+
Br
- (aq)
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
pH = 1
0.2
Na+ (aq) + F – (aq)
Initial concentration
(aq)
pH = 13.3
final concentration
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
NaF (aq)
Initial concentration
H+ (aq)
+
Br
- (aq)
pH = 1
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
0.2
Na+ (aq) + F – (aq)
Initial concentration
(aq)
pH = 13.3
final concentration
Acidic, basic, or neutral?
Acid, Base, and Salt Hydrolysis
0.1
HBr (aq)
0.0
0.1
Ca(OH)2 (aq)
0.0
NaF (aq)
Initial concentration
H+ (aq)
+
Br
- (aq)
pH = 1
0.1
0.1
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
0.2
Na+ (aq) + F – (aq)
Initial concentration
(aq)
pH = 13.3
final concentration
Basic, since HF is w.a. and
NaOH is s.b.
Will sodium and fluorine ions react with water?
Acid, Base, and Salt Hydrolysis
0.1
Initial concentration
HBr (aq)
0.0
H+ (aq)
Ca(OH)2 (aq)
0.0
NaF (aq)
Br
- (aq)
pH = 1
0.1
0.1
0.1
+
0.0
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
0.2
Na+ (aq) + F – (aq)
Initial concentration
(aq)
pH = 13.3
final concentration
Basic, since HF is w.a. and
NaOH is s.b.
Will sodium and fluorine ions react with water?
Na+ + HOH
NaOH (sb) + H+
Acid, Base, and Salt Hydrolysis
0.1
Initial concentration
HBr (aq)
H+ (aq)
0.0
0.0
Ca(OH)2 (aq)
0.0
Br
- (aq)
Final concentration
0.0
Ca2+ (aq) + 2 OH0.1
0.2
Na+ (aq) + F – (aq)
NaF (aq)
pH = 1
0.1
0.1
0.1
+
Initial concentration
(aq)
pH = 13.3
final concentration
Basic, since HF is w.a. and
NaOH is s.b.
Will sodium and fluorine ions react with water?
Na+ + HOH
NaOH (sb) + H+
Na+ + HOH
Na+ + OH- + H+
HOH
OH- + H+
No Reaction, water
cannot make water
Acid, Base, and Salt Hydrolysis
0.1
Initial concentration
HBr (aq)
0.0
H+ (aq)
Ca(OH)2 (aq)
0.0
NaF (aq)
Br
- (aq)
pH = 1
0.1
0.1
0.1
+
Final concentration
Initial concentration
0.0
0.0
Ca2+ (aq) + 2 OH0.1
(aq)
final concentration
0.2
Na+ (aq) + F – (aq)
pH = 13.3
Basic, since HF is w.a. and
NaOH is s.b.
Will sodium and fluorine ions react with water?
Na+ + HOH
NaOH + H+
s.b.
Cannot make strong
acids or bases from weak
ones
Acid, Base, and Salt Hydrolysis
0.1
Initial concentration
HBr (aq)
0.0
H+ (aq)
Ca(OH)2 (aq)
0.0
NaF (aq)
Br
- (aq)
pH = 1
0.1
0.1
0.1
+
Final concentration
Initial concentration
0.0
0.0
Ca2+ (aq) + 2 OH0.1
(aq)
final concentration
0.2
Na+ (aq) + F – (aq)
pH = 13.3
Basic, since HF is w.a. and
NaOH is s.b.
Will sodium and fluorine ions react with water?
Na+ + HOH
NaOH + H+
s.b.
Cannot make strong
acids or bases from weak
ones
Acid, Base, and Salt Hydrolysis
0.1
Initial concentration
HBr (aq)
0.0
H+ (aq)
Ca(OH)2 (aq)
0.0
NaF (aq)
Br
- (aq)
pH = 1
0.1
0.1
0.1
+
Final concentration
Initial concentration
0.0
0.0
Ca2+ (aq) + 2 OH0.1
(aq)
final concentration
0.2
Na+ (aq) + F – (aq)
pH = 13.3
Basic, since HF is w.a. and
NaOH is s.b.
Will sodium and fluorine ions react with water?
Na+ + HOH
NaOH + H+
F - + HOH
HF + OHw.a.
Cannot make strong
acids or bases from weak
ones
Acid, Base, and Salt Hydrolysis
0.1
Initial concentration
HBr (aq)
0.0
H+ (aq)
Ca(OH)2 (aq)
0.0
NaF (aq)
Br
- (aq)
pH = 1
0.1
0.1
0.1
+
Final concentration
Initial concentration
0.0
0.0
Ca2+ (aq) + 2 OH0.1
(aq)
final concentration
0.2
Na+ (aq) + F – (aq)
pH = 13.3
Basic, since HF is w.a. and
NaOH is s.b.
Will sodium and fluorine ions react with water?
Na+ + HOH
NaOH + H+
F - + HOH
HF + OHw.a.
Cannot make strong
acids or bases from weak
ones
Yes, HF weak acid and
OH- is formed, thus basic
salt!
Acid, Base, and Salt Hydrolysis
NH4Cl (aq)
NH4+ (aq) + Cl- (aq)
Acid, Base, and Salt Hydrolysis
NH4Cl (aq)
NH4+ (aq) + Cl- (aq)
acidic, basic, or neutral?
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
acidic, basic, or neutral?
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
acidic, basic, or neutral?
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
NH4+ + HOH
NH4OH + H+
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
NH4+ + HOH
NH4OH + H+
w.b.
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
w.b.
H+
This reaction is OK,
since a w.b. is formed
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
H+
w.b.
Cl- + HOH
HCl + OH-
This reaction is OK,
since a w.b. is formed
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
H+
This reaction is OK,
since a w.b. is formed
w.b.
Cl- + HOH
HCl (sa) + OH-
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
H+
This reaction is OK,
since a w.b. is formed
w.b.
Cl- + HOH
H+ + Cl- + OH-
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
H+
This reaction is OK,
since a w.b. is formed
w.b.
HOH
H+ + OH-
Again water
cannot make
water! NR
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
H+
w.b.
Cl- + HOH
HCl + OHs.a.
This reaction is OK,
since a w.b. is formed
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
H+
This reaction is OK,
since a w.b. is formed
w.b.
Cl- + HOH
HCl + OHs.a.
Cannot form s.a. from
weaker reactants, thus
N.R.
Acid, Base, and Salt Hydrolysis
HCl + NH4OH
s.a.
w.b.
NH4Cl (aq)
NH4Cl + HOH
NH4+ (aq) + Cl- (aq)
Acidic!
Will the ions from the salt combine with water?
+
NH4 + HOH
NH4OH +
H+
This reaction is OK,
since a w.b. is formed
w.b.
Cl- + HOH
HCl + OHs.a.
Cannot form s.a. from
weaker reactants, thus
N.R.
Since H+ was formed in the first reaction, then [H+] is now
greater than [OH-] making the solution acidic
Acid, Base, and Salt Hydrolysis
NaCl (aq)
Acid, Base, and Salt Hydrolysis
NaCl (aq)
Na+ (aq) + Cl-
(aq)
Acid, Base, and Salt Hydrolysis
NaCl (aq)
Na+ (aq) + Cl-
(aq) Acidic, basic, or neutral?
Acid, Base, and Salt Hydrolysis
HCl + NaOH
NaCl (aq)
NaCl + HOH
Na+ (aq) + Cl-
(aq) Acidic, basic, or neutral?
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Acidic, basic, or neutral?
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Now react each of the ions with water.
Na+ + HOH
NaOH + H+
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Now react each of the ions with water.
Na+ + HOH
NaOH + H+
s.b.
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Now react each of the ions with water.
Na+ + HOH
NaOH +
s.b.
Cannot form strong
bases from weaker
H+ ones, thus N.R.
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Now react each of the ions with water.
Na+ + HOH
NaOH +
s.b.
Cannot form strong
bases from weaker
H+ ones, thus N.R.
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Now react each of the ions with water.
Na+ + HOH
NaOH +
s.b.
Cl- + HOH
Cannot form strong
bases from weaker
H+ ones, thus N.R.
HCl + OH-
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Now react each of the ions with water.
Na+ + HOH
NaOH +
s.b.
Cl- + HOH
Cannot form strong
bases from weaker
H+ ones, thus N.R.
HCl + OHs.a.
Acid, Base, and Salt Hydrolysis
HCl + NaOH
s.a.
NaCl (aq)
s.b.
NaCl + HOH
Na+ (aq) + Cl-
(aq) Neutral!
Now react each of the ions with water.
Na+ + HOH
NaOH +
s.b.
Cl- + HOH
Cannot form strong
bases from weaker
H+ ones, thus N.R.
HCl + OHs.a.
Cannot form strong
acids from weaker
ones, thus N.R.
Buffers
Buffers are extremely important in chemistry and biology. They
maintain a nearly consistent pH in various solutions.
Buffers
Buffers are extremely important in chemistry and biology. They
maintain a nearly consistent pH in various solutions.
Our blood must maintain a pH around 7.35-7.45. If the pH is
above 7.45 you would have a condition called alkalosis. If the pH
is below 7.35, then one would suffer from acidosis.
Buffers
Buffers are extremely important in chemistry and biology. They
maintain a nearly consistent pH in various solutions.
Our blood must maintain a pH around 7.35-7.45. If the pH is
above 7.45 you would have a condition called alkalosis. If the pH
is below 7.35, then one would suffer from acidosis.
Acidosis leads to depression of the nervous system. Mild acidosis
can result in dizziness, disorientation, or fainting; a more severe
case can cause coma, or death.
Buffers
Buffers are extremely important in chemistry and biology. They
maintain a nearly consistent pH in various solutions.
Our blood must maintain a pH around 7.35-7.45. If the pH is
above 7.45 you would have a condition called alkalosis. If the pH
is below 7.35, then one would suffer from acidosis.
Acidosis leads to depression of the nervous system. Mild acidosis
can result in dizziness, disorientation, or fainting; a more severe
case can cause coma, or death.
What would happen to the pH of our blood if we were to eat
acidic foods, such as apples, oranges, or limes? What might
happen to the pH of our blood if some of the hydrochloric acid
from our stomach were to seep into our blood?
Buffers
Buffers are extremely important in chemistry and biology. They
maintain a nearly consistent pH in various solutions.
Our blood must maintain a pH around 7.35-7.45. If the pH is
above 7.45 you would have a condition called alkalosis. If the pH
is below 7.35, then one would suffer from acidosis.
Acidosis leads to depression of the nervous system. Mild acidosis
can result in dizziness, disorientation, or fainting; a more severe
case can cause coma, or death.
What would happen to the pH of our blood if we were to eat
acidic foods, such as apples, oranges, or limes? What might
happen to the pH of our blood if some of the hydrochloric acid
from our stomach were to seep into our blood? The pH would
be lower in both
Despite the possibility of pH increases or decreases, the body
maintains a nearly constant pH of 7.4. The body uses buffers to
maintain this remarkable feat.
What is a buffer and how does it work?
Despite the possibility of pH increases or decreases, the body
maintains a nearly constant pH of 7.4. The body uses buffers to
maintain this remarkable feat.
What is a buffer and how does it work?
A buffer consists of a weak acid and the salt of its conjugate base,
or a weak base and the salt of its conjugate acid.
Examples:
HF + NaOH
w.a.
NaF + HOH
c.b.
Despite the possibility of pH increases or decreases, the body
maintains a nearly constant pH of 7.4. The body uses buffers to
maintain this remarkable feat.
What is a buffer and how does it work?
A buffer consists of a weak acid and the salt of its conjugate base,
or a weak base and the salt of its conjugate acid.
Examples:
HF + NaOH
w.a.
NH3 + HCl
w.b.
NaF + HOH
c.b.
NH4Cl
c.a.
HF (g)
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
1.0 L
NaF (s)
HF (g)
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)
large
NaF (s)

H + + Fsmall
Na+ + F-
1.0 L
NaF (s)
H+ Na+
HF
F-
HCl
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)
large
NaF (s)

H + + Fsmall
Na+ + F-
Now add the strong acid HCl
HF Na+
H+
1.0 L
F-
HCl
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)
Large
NaF (s)

H + + F-
small
Na+ + F-
HF Na+
H+
1.0 L
H+
F-
Cl-
Now add the strong acid HCl
HCl
H+ + Cl- What will the pH be if just water and no
buffer?
HCl
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)  H+ + FLarge
NaF (s)
small
Na+ + F-
H+ Na+
HF
1.0 L
H+
F-
Cl-
Now add the strong acid HCl
HCl
H+ + Cl- What will the pH be if just water and no
buffer? pH = 1, dead if this is your blood.
HCl
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)  H+ + FLarge
NaF (s)
small
Na+ + F-
H+ Na+
HF
1.0 L
H+
F-
Cl-
Now add the strong acid HCl
HCl
H+ + Cl- What will the pH be if just water and no
buffer? pH = 1, dead if this is your blood.
What removes the H+ to keep the pH near 7?
HCl
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)  H+ + Fsmall
Large
NaF (s)
Na+ + F-
H+ Na+
HF
1.0 L
H+
F-
Cl-
Now add the strong acid HCl
HCl
H+ + Cl- What will the pH be if just water and no
buffer? pH = 1, dead if this is your blood.
What removes the H+ to keep the pH near 7? The conjugate base, FH + + F-
HF (a weak acid, low H+ )
NaOH
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)  H+ + FLarge
NaF (s)
small
Na+ + F-
H+ Na+
HF
1.0 L
Na+
F-
OH-
Now add the strong base NaOH
What will the pH be if just water
NaOH
Na+ + OHand no buffer?
NaOH
Buffer preparation: Add
0.10 mole HF (g) and NaF (s)
to 1.0 L of water.
HF (g)  H+ + FLarge
NaF (s)
small
H+ Na+
HF
1.0 L
Na+ + F-
Na+
F-
OH-
Now add the strong base NaOH
What will the pH be if just water and
NaOH
Na+ + OHno buffer? PH = 13, dead again
What removes the OH- to keep the pH near 7? The acid HF
HF + OH-
F- + HOH
Titration
Titration is an experimental procedure to
determine the concentration of an
unknown acid or base.
The figure on the left shows the
glassware for a titration experiment. A
buret clamp holds the buret to a ring
stand and below the buret is a flask
containing the solution to be titrated,
which includes an indicator. The
purpose of the indicator is to indicate
the point of neutralization by a color
change.
NaOH + HCl  NaCl + HOH
The picture on the left shows the
tip of a buret, with air bubble,
which is not good, and also shows
the stop-cock. Note the position
of the stop-cock is in the “off”
position. This picture shows the
color of the phenolphthalein
indicator at the end-point. In this
experiment a 23.00 mL aliquot of
0.1000 M NaOH titrant is added to
5.00 mL of an unknown HCL
solution. The acid solution in the
beaker starts out clear and
becomes pink when all of the HCL
has been consumed.
Titration
How can we calculate the concentration of acid
in the beaker?
Titration
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4, again!
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4,
again!
0.100 mole NaOH
L NaOH solution
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4, again!
0.100 mole NaOH 10-3 L solution
mL solution
L NaOH solution
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4,
again!
0.100 mole NaOH
L NaOH solution
10-3 L solution 23.00 mL soln
mL solution
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4,
again!
0.100 mole NaOH
L NaOH solution
10-3 L solution 23.00 mL soln mole HCl
mole NaOH
mL solution
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4, again!
0.100 mole NaOH
L NaOH solution
10-3 L solution 23.00 mL soln mole HCl
mole NaOH
mL solution
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4, again!
mL HCl soln.
0.100 mole NaOH 10-3 L solution 23.00 mL soln mole HCl
mole NaOH 10-3 L HCl soln.
L NaOH solution mL solution
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4, again!
0.100 mole NaOH 10-3 L solution 23.00 mL soln mole HCl
L NaOH solution
mL solution
mL HCl soln.
mole NaOH 10-3 L HCl soln.
5.00 mL
How can we calculate the concentration of acid in the
beaker?
Normal procedure, yes, a conversion. Steps 1-4, again!
0.100 mole NaOH 10-3 L solution 23.00 mL soln mole HCl
mL HCl soln.
mole NaOH 10-3 L HCl soln.
L NaOH solution mL solution
5.00 mL
=
0.460 M HCl
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid.
Below is a generic acid.
HA  H+ + Acolorless
1.
pink
Describe the color change when a strong acid is added?
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid.
Below is a generic acid.
HA  H+ + Acolorless
1.
Less pink
pink
Describe the color change when a strong acid is added?
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid.
Below is a generic acid.
HA  H+ + Acolorless
pink
1.
Describe the color change when a strong acid is added? Less pink
2.
Describe the color change when a strong base is added?
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid. Below is
a generic acid.
HA  H+ + Acolorless
pink
1.
Describe the color change when a strong acid is added? Less pink
2.
Describe the color change when a strong base is added? Darker pink
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid.
Below is a generic acid.
HA  H+ + A-
colorless
pink
1.
Describe the color change when a strong acid is added? Less pink
2.
Describe the color change when a strong base is added? Darker pink
3.
Describe the color change when the pH is lowered?
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid.
Below is a generic acid.
HA  H+ + Acolorless
pink
1.
Describe the color change when a strong acid is added? Less pink
2.
Describe the color change when a strong base is added? Darker pink
3.
Describe the color change when the pH is lowered? Less pink
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid.
Below is a generic acid.
HA  H+ + Acolorless
pink
1.
Describe the color change when a strong acid is added? Less pink
2.
Describe the color change when a strong base is added? Darker pink
3.
Describe the color change when the pH is lowered? Less pink
4.
Describe the color change when the pH is raised?
Indicators
Indicators are weak organic (carbon containing) acids of
various colors depending on the formula of the acid.
Below is a generic acid.
HA  H+ + Acolorless
pink
1.
Describe the color change when a strong acid is added? Less pink
2.
Describe the color change when a strong base is added? Darker pink
3.
Describe the color change when the pH is lowered? Less pink
4.
Describe the color change when the pH is raised? Darker pink
Color versus pH of Many Different indicators
How can we make an indicator?
How can we make an indicator?
Step One
Red Cabbage
Step Two
Cook the Cabbage
Step Three
Filter the Juice
What color is the juice after filtering?
What color is the juice after filtering? The color of pH 6, 7, or
8
Colors of cabbage juice at various pH values
The End Ch#14
ACIDS BASES AND SALTS
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