Iodine to Iodide

[24cboyd]

Hi! I am doing the Presto! From Black to Clear with the Magic of Photochemistry, and am wondering in this experiment how the iodine turns to iodide!

HI, I am doing the black to clear with photochemistry project, and the solution is not changing color under the light and I am looking for possible answers. I am using tap water instead of distilled water. I am trying to get the solution to change from the iodine color to clear under light and depending on the amount of time under light the more clear the solution will get. It has so far stayed the same and I have left it under the light for 2+ hours. If you have any idea what is causing it to not change color that would be super helpful! thank you!

Thanks!

[Administrator: Project link: https://www.sciencebuddies.org/science- ... ochemistry ]

Moderator note:

I've added your second question to your first question so the experts in this forum will see that your first question has not been answered.

I will also alert the administrator that your questions need to be answered! Thanks for your patience and best of luck with your project!

Madeline
Moderator

[JacquelineK]

Greetings fellow scientist,

I think the culprit is the tap water. There are a number of ions present in tap water (calcium, potassium, magnesium, sodium etc.) The ions from the tap water will take part in the chemical reaction and interfere in the reaction. The experiment calls for deionized water (distilled), which is free from ions and therefore these ions will not interfere in the experiment. Try again with the distilled water and that should hopefully fix the issue.

Cheers!