The Briggs-Rauscher Iodine Oscillator

This reaction is an extremely interesting reaction that is a rare phenomenon in chemistry - an oscillating reaction. Three clear solutions are combined, and the color gradually changes to amber. Suddenly, the whole thing goes dark blue! This remains for a bit, then fades back into amber and the whole cycle repeats.

The full reaction mixture is a stew of many different chemicals:
Solution A:
0.2M KIO3
0.77M H2SO4

Solution B:
0.15M malonic acid
0.02M MnSO4
Starch (very tiny amount, since it is only slightly soluble)

Solution C:
4.0M H2O2

The three are combined together in equal amounts. There are as many as 30 different reactions happening simultaneously during the reaction. The paper I mention that talks about this in great detail is titled "The Oscillatory Briggs-Rauscher Reaction. 3. A Skeleton Mechanism for Oscillations" by Noyes and Furrow. I found it online someplace, but can't seem to locate it again for free.

Anyways I hope my explanation was helpful! It took me a while to get a good grasp of it myself. As always, thanks for watching and if you have any questions please let me know.

• Category

  Science & Technology

[KonekoD]

That was really cool! As for the neutralization at the end, couldn't you set it in an ice bath to help keep the solution and container cool?

[mrhomescientist]

Yeah, that's definitely a good idea. This thing gets a little scary near the end!

[TheChemiKid]

can you use KI instead of KIO3

[mrhomescientist]

No, they are very different chemicals. Not in this version of an oscillator, anyway.

[mrhomescientist]

Funnily enough that's the exact same thing that got me my first spike in views on this video way back in February. Thanks!

[mrhomescientist]

It's a magnetic stirrer / hot plate. Very useful piece of equipment for chemistry!

[GeekyIdiot3]

Okay, thanks. And what about the molarities of the solutions? Do those have to be exact?

[mrhomescientist]

The reaction works without stirring, but without constant mixing the color changes are much, much more gradual and begin and end in different spots in the solution.

[GeekyIdiot3]

Is it a requirement, or can the reaction be performed without it?

[bonedrykneecaps]

Fantastic explanation, I could really have used this info for my school project!

[jamesmthebeau]

lol This is amazing.

[Denisse Abreu]

oH gOD! wHAT THE FUCK I JUST WATCHED? Asdfghjkl This is amazing!