This laboratory looks at the titration of Milk of Magnesia (magnesium hydroxide) with vinegar (acetic acid).
1. A dropper pipette was calibrated by counting the number of drops of vinegar needed to fill a graduated cylinder to a volume of 1.0 mL using the sample cup of vinegar from Part II and a labeled dropper pipette.
2. The number of drops was recorded in the data table.
3. The procedure was repeated two more times, the average of the three times calculated and recorded in the data table.
1. A 10% by volume solution of Milk of Magnesia was made with distilled water using the graduated cylinder. 100 mL of solution was made and mixed thoroughly.
2. 10.0 mL of the Milk of Magnesia solution was measured out using the graduated cylinder and added to the 50 mL beaker.
3. The pH of the solution was determined using the pH meter and recorded in the data table.
4. The Milk of Magnesia solution was titrated with vinegar, adding 5 drops of vinegar at a time. After each 5 drops was added, the beaker was swirled and the pH allowed to come to equilibrium, then the value was read and recorded in the data table.
5. This process was continued until the pH no longer changed with the addition of more vinegar.
1. The volume of vinegar added at each step was calculated from the calibration of the dropper, and the cumulative volume of vinegar added for each pH value was calculated and recorded.
2. A titration curve was drawn using the Graphical Analysis software from the laboratory kit, which is a graph of pH vs. volume of titrant (vinegar).