Neutralization and
Titrations!
Neutralization Reactions
• Reactions in which an acid and a base
react in an aqueous solution to produce a
salt and water.
HCl + NaOH  NaCl + H2O
What types of reactions are these?
Double Displacement
Acid + Base  Salt + Water
YOUR TURN: Complete & Balance the reactions.
Then, circle & name the salt for each reaction.
___H
2 3PO4 + ___
3 Ca(OH)2  ___H
6 2O + ___Ca3(PO4)2
Calcium phosphate
___H2SO4 + ___
2 KOH  ___H
2 2O + ___K2SO4
Potassium sulfate
TITRATIONS!
Titrations!
What is a titration?
The process of adding a known amount of
solution of known concentration to determine
the concentration of another solution.
Involves the addition of an acid to a base
or a base to an acid.
Equivalence Point
When the number of moles of hydrogen ions
equals the number of moles of hydroxide ions.
HCl + NaOH  NaCl + H2O
1 mole
1 mole
1 mole
1 mole
H2SO4 + 2NaOH  Na2SO4 + 2H2O
1 mole
2 mole
1 mole
2 mole
2HCl + Ca(OH)2  CaCl2 + 2H2O
2 mole
1 mole
1 mole
2 mole
How many moles of HCl will it take to neutralize 6 moles of
NaOH?
6 moles HCl
How many moles of HCl would it take to neutralize 6 moles of
Ca(OH)2?
12 moles HCl
How many moles of NaOH would it take to neutralize 6 moles
of H2SO4?
12 moles NaOH
How many moles of H3PO4 would it take to neutralize 9 moles
of Ca(OH)2?
6 moles H3PO4
How many moles of H3PO4 would it take to neutralize 6.4
moles of Ca(OH)2? 2 H3PO4 + 3 Ca(OH)2  6 H2O + Ca3(PO4)2
6.4 mol Ca(OH)2
(
2 mol H3PO4
3 mol Ca(OH)2
)=
4.3 mol
H3PO4
Harder examples: Balance the neutralization reaction first:
2 3PO4 + ____
3 Ca(OH)2  ____ Ca3(PO4)2 + ____H
6
___H
2O
a. How many moles of Ca(OH)2 will it take to neutralize 3 moles of H3PO4?
3 mol H3PO4
(
(
3 mol Ca(OH)2
2 mol H3PO4
)=
)=
4.5 mol
Ca(OH)2
b. How many liters of 1.5 M Ca(OH)2 will it take to neutralize 1.2 moles of H3PO4?
1.2 mol H3PO4
3 mol Ca(OH)2
2 mol H3PO4
1.8 mol Ca(OH)2
÷ 1.5 M =
1.8 mol Ca(OH)2
1.2 Liters
c. How many liters of 2.9 M H3PO4 will it take to neutralize 300 mL of 0.7 M
Ca(OH)2?
0.3 L x 0.7 M = 0.21 mol Ca(OH)2
0.21 mol Ca(OH)2
0.14 mol H3PO4
(
2 mol H3PO4
3 mol Ca(OH)2
÷ 2.9 M =
)=
0.14 mol
H3PO4
0.05 Liters
End Point
The point at which the indicator changes color is
an end point.
Steps for Titration Calculations
1. Start by writing a balanced (neutralization)
equation (to determine mole to mole ratios).
Neutralization reactions are always double
displacement reactions.
2. Write down all of your information underneath the
chemical equation.
3. Determine moles known (Acid/Base). M x L =
moles
4. Use mole to mole ratio to determine moles of
unknown (Acid/Base).
5. Determine molarity of unknown (mol/L)
Thinking problem: Let’s say you had to add 200
mL of 1.0 M NaOH to 200 mL of HCl before the
indicator turned pink. What molarity must the acid
have?
1 M HCl
Thinking problem #2: What if you had to add 400
mL of 1.0 M NaOH to 200 mL of HCl before the
indicator turned pink. What molarity must the acid
have?
2 M HCl
Titration Problem #1
A 25 mL solution of HCl is completely neutralized by 18 mL of
1.0M NaOH. What is the concentration of the HCl solution?
HCl + NaOH  NaCl + H2O
0.018 L NaOH x
1.0 mol NaOH = 0.018 mol NaOH
1 L NaOH
0.018 mol NaOH x 1.0 mol HCl
= 0.018 mol HCl
1.0 mol NaOH
0.018 mol HCl
0.025 L
=
0.72 M
YOUR Titration Problem
15.0 mL of 1.50 M HCl is titrated with 10.8 mL of NaOH.
Determine the molarity of the sodium hydroxide solution. Write
the reaction first:
HCl + NaOH  NaCl + H2O
0.015 L HCl
x
1.5 mol HCl
1 L HCl
= 0.0225 mol HCl
0.0225 mol HCl x 1.0 mol NaOH = 0.0225 mol NaOH
1.0 mol HCl
0.0225 mol NaOH
0.0108 L
=
2.08 M
And one more…
You have a 200 mL sample of NaOH of an unknown
concentration. It takes 75 mL of a 1.25 M H2SO4 in order to
neutralize the solution. What is the concentration of NaOH?
Write the reaction first:
H2SO4 + 2 NaOH  Na2SO4 + 2 H2O
0.075 L H2SO4 x 1.25 mol H2SO4 = 0.094 mol H2SO4
1 L H2SO4
0.094 mol H2SO4 x 2 mol NaOH = 0.188 mol NaOH
1 mol H2SO4
0.188 mol NaOH
0.2 L
=
0.94 M
Formula of Base
NaOH
Formula of Acid
Molarity of Base
Amount of acid in
flask
Initial Buret reading
HCl
0.2 M NaOH
15.0 mL
Final Buret reading
Amount of base
added (take final
buret – initial buret)