Percent Acetic Acid in Vinegar Lab

Last week in chemistry class, we completed a three day lab to determine the percent of acetic acid in vinegar. In order to be able to do this lab, we had to memorize the procedure. First, we added 100mL of NaOH to our buret and then mixed around .5 grams of KHP with water in a flask. After the KHP was dissolved, we added 3 drops of phenolphthalein to act as our indicator. Then we titrated this using the NaOH in the buret, until the solution turned and stayed pink. Then we recorded how much NaOH was used. After this, we repeated these same steps, but with vinegar in our flask, instead of all water. This lab was really interesting, and it was a challenge to try and get the solution to turn pink without making it too dark. Here is a website that I found that explains how titrations work: How to Titrate

This is what it looked like when the NaOH reacted and started to form a pink color.

This is what the solution in the flask looked like after we were done titrating and it was staying light pink.

This is what the whole funnel/buret set-up looked like.