# Does this 'Belousov-Zhabotinsky Reaction' kit contain the correct reagents?

I want to run the Belousov–Zhabotinsky reaction as a demonstration. As far as I'm aware, you need sodium bromate, sodium bromide, water to $\pu{100 ml}$, malonic acid, phenanthroline and ferrous complex. This is the recipe that I know, but I can't get hold of the right ingredients.

I found this kit entitled 'Belousov-Zhabotinsky Reaction' for £15.00. I am not sure it has the right ingredients:

Kit contents: Iodine sodium, malonic acid, Sulfamic Acid, sodium thiosulfate Manganese sulfate, starch solution, cups 5 pieces, chemicals, racks etc.

Does this kit have the right ingredients for the Belousov–Zhabotinsky reaction?

No, it doesn't, at least not strictly.

One of the most common variations on this reaction uses malonic acid $(\ce{CH2(CO2H)2})$ as the acid and potassium bromate $(\ce{KBrO3})$ as the source of bromine. The overall equation is:

$$\ce{3CH2(CO2H)2 + 4BrO3− → 4Br− + 9CO2 + 6H2O}$$

[ $\ldots$ ]

Many variants of the reaction exist. The only key chemical is the bromate oxidizer.

The kit doesn't contain any bromide or bromate, so by definition it will not allow demonstration of a Belousov–Zhabotinsky reaction.

However: It does appear that the kit may allow demonstration of an iodine clock reaction:

### Hydrogen peroxide variation

This reaction starts from a solution of hydrogen peroxide with sulfuric acid. To this is added a solution containing potassium iodide, sodium thiosulfate, and starch.

The ingredients are not a perfect match, and actually appear to be something of a mishmash between the iodine clock reaction and the Belousov–Zhabotinsky reaction, but they're in the right ballpark. Metal ions and their oxides are well known as catalysts for hydrogen peroxide decomposition, and "Sulfamic acid" could be a typo that was supposed to be "sulfuric acid".

• en.wikipedia.org/wiki/Sulfamic_acid Close enough in terms of properties, I guess. – orthocresol Mar 31 '17 at 14:10
• @orthocresol <nod>, as long as it's just acidifying the matrix, it should probably work ok. – hBy2Py Mar 31 '17 at 14:13