Belousov-Zhabotinsky oscillating reaction

[Feynmanfan]

Here's a physics student trying to perform the Belousov experiment, that is the chemical clock that changes its color from red to blue and viceversa.

I've been able to "borrow" the following reactants:

H2S04(sulfuric acid) 1,5M
NaBr03(sodium bromate) 0.08M
CH2(COOH)2(malonic acid) 0.002M
Ce(SO4)2 0.1M
ferroin 0.0003.M

I've tried mixing them but I've seen no oscillations. The original recipe says that Ce2(SO4)3 should be used (Ce3+//Ce4+ is what oscillates). What do you suggest I should do? In what order do I mix the reactants? Is this a bad recipe?
Thanks for your help!

 

[Gokul43201]

1. I think your malonic acid is too dilute. I recommend 0.2 to 0.3M acid.

2. The order of mixing should not matter.

3. I think your Ce(SO4)2 is too concentrated. I would use something like 0.002M Ce(4+) solution. Or did you just switch the concentrations of the acid and ceric sulfate when you typed it here ?

4. If switching the concentrations doesn't help (or you just mistyped it here), you could try ceric ammonium nitrate instead of ceric sulfate.

5. What color do you see when you prepare the solution ?

6. The typical period of oscillations for the specified concentrations is of order a minute. So, you need to have the solution be stirred continuously for at least that long to see a color change. A better idea (once you have a working solution, at least) is to use a magnetic stirrer.

 

[Blueshift5]

I would suggest that you follow the original recipe for the Belousov-Zhabotinsky oscillating reaction. The use of Ce2(SO4)3 as the catalyst is crucial for the oscillations to occur. The presence of Ce3+ and Ce4+ ions is what drives the oscillations.

In terms of the reactant order, it is important to mix the reactants in a specific order to achieve the desired oscillations. Typically, the reactants are mixed in the following order: malonic acid, sulfuric acid, sodium bromate, and then the catalyst (Ce2(SO4)3). It is important to note that the concentrations of each reactant should also be carefully controlled to ensure the proper oscillations.

It is possible that the recipe you have is not a reliable one for the Belousov-Zhabotinsky reaction. I would recommend consulting with other scientists who have experience with this reaction or referring to established literature on the subject for a more reliable recipe.

Overall, it is important to carefully follow the instructions and use the correct reactants in order to successfully perform the Belousov-Zhabotinsky oscillating reaction. I wish you the best of luck in your experiments.