best iodine for the starch test

scienceboy · Post by **scienceboy** » Wed Apr 05, 2006 6:19 am

My son is doing a project on the effects Iodine has with food with and without starch. Is there a specific type of iodine that should be used. I have read that Lugol's solution is best but will others work?

deleted-71487 · Post by **deleted-71487** » Wed Apr 05, 2006 4:59 pm

Lugol solution is the right stuff for this.

It's basically just a mixture of elemental iodine and potassium iodine (which produces iodine ions). The reaction that produces the blue/black color works best (only?) in the presence of both elemental and ionic iodine.

Or at least that what I've been able to determine by googling for "starch test iodine". I'm not a chemist, but that seems to be the pretty consistent answer in a lot of places.