"In the presence of HCl, KIO3 reacts with KI to both form iodine, which then oxidises the ascorbic acid to dehydroascorbic acid, and it itself is reduced to iodide ions. When all the ascorbic acid is oxidised, the excess iodine is free to react with the starch indicator, creating the light tan endpoint."
Gah. I took one Chem class, and that's it for me. :l Now I'm in Physics, and nest year I'll take Biology. Least amount of science classes I can get. I'm more of an artsy person. :/ My Chem teacher was cool though. He was like the Dumbledore of our school. XD