dessskris Posted February 10, 2011 Report Share Posted February 10, 2011 (edited) right, in this experiment I am told that an oxidant X is KIO3 (aq).in the presence of acid, oxidant X oxidises iodide ions to iodine.1 mole of X produces 3 moles of I2.What I did next was titrating the iodine liberated with thiosulfate ions to reduce the iodine back to iodide.I am stuck with CE and I thought I would just suggest another type of experiment using starch solution. Unfortunately I can't think of one! Does anybody know how a redox experiment involving KIO3, I2 and starch in order to find the Mr of KIO3?Thank you! Edited February 10, 2011 by Desy ♫ Reply Link to post Share on other sites More sharing options...
Drake Glau Posted February 12, 2011 Report Share Posted February 12, 2011 Wouldn't it end up the same? It's the still the same redox with acid+KIO3 isn't it? Starch will react with the iodine so it should give another substance that will help you determine the molecular mass thing but just with a different substance for titration. Reply Link to post Share on other sites More sharing options...
dessskris Posted February 12, 2011 Author Report Share Posted February 12, 2011 yeah same reaction but during the titration can starch be used somehow?Because when I did my titration there were a colour change already without adding any indicator (starch) but idk why. Is there any reaction with KIO3 in which there is no colour change (starch is needed)? Reply Link to post Share on other sites More sharing options...
Drake Glau Posted February 13, 2011 Report Share Posted February 13, 2011 Well the reaction forming the I2 will make the solution pretty dark since iodine is a really dark purple color to begin with. Now that I think about it using starch as the indicator might not work out so well. Iodine will make the starch dark, but starch will just turn dark as you add it and it will look just like the iodine so that isn't going to help any really =/I don't know the color of KIO3 but any redox reaction with it is likely going to make iodine, always, just because of the IO3 there. This is going to probably always cause a major color change before you start titrating anything.I'm running out of ideas, we never really went through titration or anything like this so all I can work with is my redox knowledge =/ 1 Reply Link to post Share on other sites More sharing options...
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