Science Buddies: "Ask an Expert"

I am studying the effects of different lights on iodine/oxalate solution. My reference samples of iodine tincture and water are very orange at 20 drops mixed with 9ml water. However when 10 drops of iodine are added to 4ml of the oxalate and ammonia solution (2.5g oxalate acid - 25ml distilled water - 25ml ammonia) to make iodine/oxalate solution the color is a very pale grey. So comparing the sample against the reference looks off. Any thoughts why the colors don't look the same?

I'm not a chemist, but perhaps I can help.

Are you running the experiment described here: https://www.sciencebuddies.org/science- ... p095.shtml ?

If so, note what the author says at the beginning of the "Experimental Procedure": "This procedure will require some creative problem-solving since the ingredients and the equipment may vary, depending on your experimental setup. Varying the sources and concentrations of the reactants will provide many opportunities for further experimentation.

Note from author: When I tested this procedure I found that the mixture of ammonia and iodine tincture, without the addition of oxalic acid, yielded a black-colored solution that was very sensitive to sunlight. As an option, try the procedure with and without oxalic acid."

Perhaps this is what you have encountered.

Good luck.