1. Titration
What is the concentration in moles/liter of a vinegar (solution of acetic acid in water)?

2. Titration
Titration – experimental method of determining the concentration of a solution
Purpose: To determine the concentration of a solution of commercial vinegar (solution of acetic acid dissolved in water) by reaction with known amount of sodium hydroxide

3. Prelab Question #1: Vinegar Concentration on label = 5
Prelab Question #1: Vinegar Concentration on label = 5.0 % mass/volume – calculate molarity
% = part/ 100
5.0 % m/v = 5.0 g CH3COOH/ 100 mL Solution
Molarity = moles CH3COOH/ L of Solution
Molar Mass C2H4O2 :
C2: H4: O2: = g/mole

4. Prelab Question #1: Vinegar Concentration on label = 5
Prelab Question #1: Vinegar Concentration on label = 5.0 % mass/volume – calculate molarity
Molar Mass C2H4O2 :
C2: H4: O2: = g/mole ( )
1 mole C2H4O2
5.0 g C2H4O2 =
0.083 moles
60.06 g C2H4O2
Molarity =
0.083 moles C2H4O2 =
0.83 M
0.100 L
Use 0.83 M as accepted value in final lab % error calculations

5. H2O + CH3COO-1 + Na +1 CH3COOH + NaOH → CH3COOH + Na + + OH-1 →
Prelab #2: Write the balanced equation for the reaction of acetic acid CH3COOH and sodium hydroxide, NaOH
Important hints: This is an acid-base reaction; What is an acid? What is a base? Which is which? NaOH is an ionic base – don’t forget to separate it into ions before reacting it.
CH3COOH + NaOH →
CH3COOH + Na OH-1 →
H2O
+ CH3COO-1
+ Na +1
Link to acetic acid NaOH reaction
Link to acid base titration animation Chang

6. Titration Equation for acid-base rxn with 1:1 Stoichiometry
MAVA = MBVB
MA = Molarity of acid MB = Molarity of Base
VA = Volume of acid VB = Volume of Base
Concept: Moles acid x Liter = Moles Base x Liter
Liter
Liter
HA HA HA
NaOH NaOH NaOH
H2O H2O H2O NaA NaA NaA

7. 3A) Acetic acid, sodium hydroxide, sodium acetate and water are all clear and colorless. What color is the Phenolpthlalein indicator in acidic solution and what color is it in basic solution?

8. At endpoint : moles acid = moles of base
3B) What is the endpoint of a titration? What change will you observe in the solution when the endpoint is reached?
At endpoint : moles acid = moles of base
Endpoint
Past Endpoint
Start

10. HInd H+ H+
OH-1 H+

11. HInd H+
H2O H+

12. HInd H+
H2O H+
OH-1

13. HInd H+
H2O
H2O

14. HInd H+
OH-1
H2O
H2O

15. HInd
H2O
H2O
H2O

16. OH-1
HInd
H2O
H2O
H2O

17. Ind -1
H2O
H2O
H2O
H2O

18. Titration Equation for acid-base rxn with 1:1 Stoichiometry
MAVA = MBVB
MA = Molarity of acid MB = Molarity of Base
VA = Volume of acid VB = Volume of Base
Concept: Moles acid x Liter = Moles Base x Liter
Link to acetic acid NaOH reaction
Link to acid base titration animation Chang
Liter
Liter
HA HA HA
NaOH NaOH NaOH
H2O H2O H2O NaA NaA NaA

19. Example Calculation of ∆Vbase
Initial Volume = mL
Final Volume = mL
∆Vbase = Vf – Vi = – mL = mL

20. Sample Data Table and Calculation
MAVA = MBVB
Acid Base
MA = ? MB = 0.50 M
Volume Final: mL Volume Final: mL
- Volume Initial: 0.00 mL Volume Initial: mL
VA = mL VB = mL
MA = MBVB
= (0.50 M) (11.03 mL)
= .55 M VA
10.05 mL

21. Link to titration technique video
Link to reading meniscus
Link to measuring volume
Link to acetic acid NaOH titration