Antacids!
CHM2046L
Spring 2017
Key Question:
Which antacid is the best at neutralizing
stomach acid?
Introduction to Phenolphthalein
Color change at pH= 8-10
In basic conditions it is pink. At pH 7 it is
colorless and stays colorless throughout the
acidic region
Key Question: Which antacid is the best at
neutralizing stomach acid?
Important notes:
• CO2 (aq) (a common product) can act as a buffer during
the titration. Gently heating your acid removes CO2. Let
cool before analysis.
• Conduct multiple trials until three of them come within
0.1 mL of each other.
Strategies for Success
• Do one rough estimate trial
• Keep previous trials as visual aids
• Don’t go beyond burette graduations
• Use the most accurate glassware as possible
• Pay attention to endpoint (it often comes suddenly)
• Dark pink = too much NaOH!