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8. Vinegar Titration Lab

Purpose:

Determine the concentration of acetic acid in vinegar.

Procedure:

1. 1. Using a clean funnel, fill a buret with NaOH solution, which was determined to have a molarity of 1.00M. Record the initial volume of NaOH in the buret.
   2. Measure out 10mL of vinegar using a graduated cylinder. Transfer the vinegar into an Erlenmeyer flask. Add 2 drops of phenolphthalein to the flask.
   3. Slowly add the 1.00M NaOH to the vinegar in 1-2mL increments. As the endpoint nears. the color change of the indicator slows. If you feel that you need less than a drop of NaOH, wash the tip of the buret and walls of the fask was a very small amount of distilled water. Continue to add NaOH until the endpoint is reached. Record the final volume of NaOH in the buret.
   4. Refill the buret if necessary and repeat the titration process at least 2 more times.
   5. Calculate the molarity of the NaOH solutions for each trial.
   6. Calculate the percent deviation between the trials. (high-low)/avg*100)
   7. If the % deviation is greater than 2%, repeat the titration process.