In this experiment, students will titrate milk
of magnesia (a common laxative medicine) with
vinegar (an acid used daily, like dilute acetic
acid). The purpose of this experiment is to
determine how strong of a base milk of magnesia
is. This simple experiment tests students’
knowledge of acid/base chemistry and also introduces
a practical application of chemistry.
1. Milk of Magnesia
2. Red Cabbage Extract (Indicator)
3. White Vinegar
4. Optional--Rice Vinegar
1. Graduate cylinder or another type of measuring
2. Flask or a beaker
*Tip: Milk of Magnesia is a thick substance
that will adhere to the sides of the flask or
beaker. Be sure to use a dilute solution before
titrating, to ensure that no volume of milk
of magnesia is lost. Directions on diluting
are in the methods*
Methods (Part I):
1. Take 1 mL of milk of magnesia and dilute
it with 10 mL of distilled water.
2. Place the prepared solution from above in
a beaker or a flask.
3. Add 4 drops of red cabbage extract, as an
indicator, to the milk of magnesia solution
(a green color should appear).
4. Add white vinegar (drop by drop using a
buret or an eye dropper) to the milk of magnesia
solution. This should be done until the green
1. How many mL of white vinegar was added to
the green milk of magnesia solution to turn
it back to white?
Methods (Part II):
1. Repeat the above experiment using rice vinegar
instead of white vinegar.
1. How many mL of rice vinegar was added to
change the color of milk of magnesia from green