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Acids & Bases
STRONG
_ completely ionized
_ strong electrolyte
_ ionic/very polar bonds
bonds
Strong Acids:
HClO4
H2SO4
HI
HBr
HCl
HNO3
vs
WEAK
_ partially ionized
_ weak electrolyte
_ some covalent
Strong Bases:
LiOH
NaOH
KOH
Ca(OH)2
Sr(OH)2
Ba(OH)2
TITRATION
Titration of a strong acid with a strong base
ENDPOINT = POINT OF NEUTRALIZATION =
EQUIVALENCE POINT
At the end point for the titration of a strong acid with a strong
base, the moles of acid (H+) equals the moles of base (OH-) to
produce the neutral species water (H2O). If the mole ratio in
the balanced chemical equation is 1:1 then the following
equation can be used.
MOLES OF ACID = MOLES OF BASE
nacid = nbase
Since M=n/V
MAVA = MBVB
TITRATION
MAVA = MBVB
1. Suppose 75.00 mL of hydrochloric acid was required to
neutralize 22.50 mLof 0.52 M NaOH. What is the molarity of
the acid?
HCl + NaOH  H2O + NaCl
Ma Va = Mb Vb rearranges to Ma = Mb Vb / Va
so Ma = (0.52 M) (22.50 mL) / (75.00 mL)
= 0.16 M
Now you try:
2. If 37.12 mL of 0.843 M HNO3 neutralized 40.50 mL of KOH,
what is the molarity of the base?
Mb = 0.773 mol/L
Molarity and Titration
TITRATION
Titration of a strong acid with a strong base
ENDPOINT = POINT OF NEUTRALIZATION =
EQUIVALENCE POINT
At the end point for the titration of a strong acid with a strong
base, the moles of acid (H+) equals the moles of base (OH-)
to produce the neutral species water (H2O). If the mole
ratio in the balanced chemical equation is NOT 1:1 then
you must rely on the mole relationship and handle the
problem like any other stoichiometry problem.
MOLES OF ACID = MOLES OF BASE
nacid = nbase
Molarity and Titration
• A student finds that 23.54 mL of a 0.122 M
NaOH solution is required to titrate a 30.00-mL
sample of hydr acid solution. What is the
molarity of the acid?
• A student finds that 37.80 mL of a 0.4052 M
NaHCO3 solution is required to titrate a 20.00mL sample of sulfuric acid solution. What is the
molarity of the acid?
• The reaction equation is:
H2SO4 + 2 NaHCO3 → Na2SO4 + 2 H2O + 2 CO2
Water Equilibrium
Water Equilibrium
Kw = [H+] [OH-] = 1.0 x 10-14
Equilibrium constant for water
 Water or water solutions in which [H+] = [OH-] = 10-7 M
are neutral solutions.
 A solution in which [H+] > [OH-] is acidic
 A solution in which [H+] < [OH-] is basic
pH
A measure of the hydronium ion
• The scale for measuring the hydronium ion concentration
[H3O+] in any solution must be able to cover a large range. A
logarithmic scale covers factors of 10. The “p” in pH stands for
log.
• A solution with a pH of 1 has [H3O+] of 0.1 mol/L or 10-1
• A solution with a pH of 3 has [H3O+] of 0.001 mol/L or 10-3
• A solution with a pH of 7 has [H3O+] of 0.0000001 mol/L or 10-7
pH = - log [H3O+]
The pH scale
The pH scale ranges from 1 to 10-14 mol/L or from 1
to 14.
pH = - log [H3O+]
1 2 3 4 5 6 7 8 9 10 11 12 13 14
acid
neutral
base
Manipulating pH
Algebraic manipulation of:
pH = - log [H3O+]
allows for:
[H3O+] = 10-pH
If pH is a measure of the hydronium ion
concentration then the same equations could be
used to describe the hydroxide (base)
concentration.
[OH-] = 10-pOH
pOH = - log [OH-]
thus:
pH + pOH = 14 ; the entire pH range!
PRACTICE PROBLEM #25
1. How many milliliters of 1.25 M LiOH must be added to neutralize
34.7 mL of 0.389 M HNO3?
10.8 mL
2. What mass of Sr(OH)2 will be required to neutralize 19.54 mL of
0.00850 M HBr solution?
0.0101 g
3. How many mL of 0.998 M H2SO4 must be added to neutralize 47.9
mL of 1.233 M KOH?
29.6 mL
4. What is the molar concentration of hydronium ion in a solution of
pH 8.25?
-9
5.623 x 10 M
5. What is the pH of a solution that has a molar concentration of
hydronium ion of 9.15 x 10-5?
pH = 4.0
6. What is the pOH of a solution that has a molar concentration of
hydronium ion of 8.55 x 10-10? pOH = 4.9
GROUP STUDY PROBLEM #25
______1. How many milliliters of 0.75 M KOH must be added to neutralize
50.0 mL of 2.50 M HCl?
______2. What mass of Ca(OH)2 will be required to neutralize 100 mL of
0.170 M HCl solution?
______3. How many mL of 0.554 M H2SO4 must be added to neutralize
25.0 mL of 0.9855 M NaOH?
______ 4. What is the molar concentration of hydronium ion in a solution
of pH 2.45?
______ 5. What is the pH of a solution that has a molar concentration of
hydronium ion of 3.75 x 10-9?
______ 6. What is the pOH of a solution that has a molar concentration of
hydronium ion of 4.99 x 10-4?

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