Titrations 19.4
Calculations involving
neutralization reactions
Learning Objectives
• Understand the neutralization reaction …
strong acid and base reaction
• Concept of titration, end point, and
equivalence point and how they relate to
neutralization reaction
• How to solve titration problems … how to
determine unknown acid or base
concentration
Neutralization Reaction
• Acid + Base  Salt + Water
–Called a neutralization reaction
–Is a double replacement reaction
–Requires use of an indicator to
identify neutralization point
• Strong acid + Strong base = neutral
solution
–If # of H+ = # of OH-
Titration
• A titration is a reaction where
a solution of known
concentration (standard
solution) is used to identify a
solution of unknown
concentration
Practical Examples of Titrations
• Determining blood glucose levels.
• Determination of medical proportions
in a IV drip.
• Amount of salt and sugar in food.
• Level of acidity in wine and cheese.
• Level of acidity in fresh water
samples.
End Point
• The end point of a titration is
when the solution just barely
changes color
• The equivalence point is the
point where the acid and base
exactly react with one another
• Ideally, the end point should
be the same as the
equivalence point
Titration Calculation
In a titration, 27.4 ml of a 0.0154 M HCl
solution is added to 20.0 mL sample of NaOH
solution of unknown concentration. What is
the molarity of the basic solution?
HCl(aq) + NaOH(aq)
SA
SB
H2O(l) + NaCl(aq)
Neutralization
First we need to figure moles of HCl used to
neutralize NaOH in reaction.
0.0274 L x 0.0154 mol/L = 4.22 x 10-4 mol of HCl
Titration Calculation
= 4.22 x 10-4 mol of HCl
HCl(aq) + NaOH(aq)
H2O(l) + NaCl(aq)
= 4.22 x 10-4 mol of NaOH
M of NaOH = 4.22 x 10-4 mol of NaOH
.0200 L
M of NaOH = .021 M
Titration Endpoint
How can you tell when you
have added enough NaOH?
Titration Curve
Titration Calculation Shortcut
• Objective: to find the M of the unknown
acid or base.
• Use a balanced chemical equation to
determine the mole/mole ratio of acid
to base.
MaVana=MbVbnb
• M = molarity
• V = volume
• n = # of H3O+ ions in the acid or OH- ions in the base. (if
there are no OH- ions in the base, n = 1)
Cool Down
• How many moles of sulfuric acid
are required to completely
neutralize 0.50 mol of sodium
hydroxide?
• How many moles of potassium
hydroxide are needed to
completely neutralize 1.56 mol of
phosphoric acid?