1. Calculations involving neutralization reactions
Titrations 19.4
Calculations involving neutralization reactions

2. 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

3. 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-

4. Titration
A titration is a reaction where a solution of known concentration (standard solution) is used to identify a solution of unknown concentration

5. 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.

6. 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

7. Titration Calculation
In a titration, 27.4 ml of a 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) H2O(l) + NaCl(aq) SA SB
Neutralization
First we need to figure moles of HCl used to neutralize NaOH in reaction.
L x mol/L
= x 10-4 mol of HCl

8. Titration Calculation
= x 10-4 mol of HCl
HCl(aq) + NaOH(aq) H2O(l) + NaCl(aq)
= x 10-4 mol of NaOH
M of NaOH = x 10-4 mol of NaOH
.0200 L
M of NaOH = .021 M

9. Titration Endpoint
How can you tell when you have added enough NaOH?

10. Titration Curve

11. 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)

12. 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?