[susdujcrd]

During an experiment to determining concentration of Vit. C in several solutions (using iodometry),
I had a beeker with 20mL ascorbic acid solution and 3mL sulfuric acid.
I then added 30 ml Potassium iodate and the solution turned to dark brown instantly, indicating the presence of iodine.
According to the procedure, this liberation of iodine was supposed to happen only after adding Potassium iodide to react with the iodate.
My instructor said that probably the beaker wasn't clean before the experiment and had traces of KI in it, even though I washed it prior to the event.

Is it possible to create iodine from just Vit C, sulfuric acid and potassium iodate?

[Hunter2]

Well, it depends of the amounts. Probably ascorbic acid reduced the iodate to iodide and excess of it released the iodine.