Titration Curves of
Strong and Weak
Acids and Bases
Maureen C. Miller
Chatham Hall
AP Chemistry
Grades 11, 12
 To react the following combinations of acids and bases
HCl (strong acid)
NaOH (strong base)
HCl (strong acid)
NH3 (weak base)
HC2H3O2 (weak acid) HC2H3O2 (weak acid)
NaOH (strong base) NH3 (weak base)
To compare empirical equivalence points and pH on graph to calculated
values from pre-lab.
To become more familiar with titration curves by observing
differences in initial pH and length of the vertical region of the
curve near the eq.pt.
To determine the most suitable indicator for each of the four
reactions.
1. Given a sample titration curve, students will correctly identify
a reaction between weak and strong acids and bases
2. Given a sample titration curve, students will correctly
choose a suitable indicator for the equivalence point.
3. Given a specific acid and base of known concentration,
students will correctly determine the pH at the equivalence point.
Vernier data TI Graphing Verneir pH
collector
Calculator
Amplifier
and pH
electrode
250 mL 50 mL buret Ring stand
beaker
Phenolthathalein
indicator
8 mL
0.10 M HCl
8 mL
0.10 M
HC2H3O2
Verneir
Adapter
Cable
Stop Watch
2 utility
clamps
100 mL
dH2O per
trial
50 mL
0.10 M
NaOH
50 mL
0.10 M
NH3
 Obtain safety goggles!
Place 8 mL of acid solution into a 250-mL
beaker. Add approximately 100-mL water. Add
3 drops of phenolphthalein indicator solution.
Fill buret with 50-mL base.
Connect the pH amplifier to the Verneir data collector and
to computer
In the Logger Pro Program, open Probes and Sensor, pH
Sensor. Select pH versus Time.
 Under Experiment, select Sampling. Set Experiment
Length to 240 seconds and sampling speed to 3 samples per
second.
Once you are ready to begin collecting data, press “collect
data” and open the stopcock to provide a constant slow drip.
At the same time, start the stop watch.
Swirl the solution with the pH electrode. Be sure to note the
time (in seconds) when the solution turns from clear to pink.
Strong Acid / Weak Base
Strong Acid / Strong Base
Weak Acid / Strong Base
Weak Acid / Weak Base
Students will complete the following:
Pre-Lab Assignment
Purpose
Procedure
Data: labeled graphs, time of phenolphthalein color
change
Conclusion Questions
Great Lab to visualize the change in pH as base is
added!
Although we did the lab using the TI calculator and
computer, we found the computer to:
be much easier to set-up
provide a more accessible visual to all
students
be easier to manipulate data after the
completion of the lab
give nice print out that students can use
directly in their reports
Acknowledgements
Thanks to everyone who made this laboratory experience
successful:
My AP students, Michelle, Emily, Sara and Ebony,
for always working so hard,
My technology savior, Mr. David Lyle, who spent countless
hours with me connecting wires and making this lab possible
My friend and colleague, Mrs. Molly Thomas,
for emotional support!!
All the teachers and staff at Pittsylvania County
Schools, for inviting us to this workshop. It was
wonderful!