Vitamin C Lab

Approximately 100 mL of iodine, a dark blue liquid, was poured into a beaker and about 150 mL of water, a clear liquid, was added to the same beaker, making the liquid about 250 mL in volume. In a flask, 0.11 g of white, powdery vitamin C was measured then 100 mL of water was added to the flask. 20 drops (which is about 1 mL) of starch indicator, a clear liquid, were put in as well. While the buret was at eye level and over the sink, it was rinsed out three times to coat the inside of the glass in the iodine solution. That little bit of solution was used to get rid of air bubbles by unsealing the buret and letting a few drops go through. The buret was then filled close to the zero marking and the initial reading was written down. The solution of iodine was slowly added to the liquid of water, vitamin C, and starch in the flask. The flask was being swirled as the iodine was being titrated. As soon as the liquid in the flask turned blue, the buret was sealed. The final reading of the iodine left in the buret was written down. This process was repeated two more times with iodine solution and once with orange tang as the liquid in the flask (1 mL of starch was also added in this titration).