[tash]

I'm doing a practical experiment in class at the moment which is investigating the effect of changes in concentration of the reactants on the rate of reaction between acidified iodine and acetone.

From my research I have discovered that the reaction has an order of zero with respect to iodine concentration. So, basically the concentration of iodine has no effect on the reaction rate. I am having trouble finding why the concentation of iodine has no effect...
So if anybody knows why I would greatly appreciate your help.

Thanks,
tash

FYI: reaction between iodine and acetone occurs as follows-

CH₃COCH₃ (aq) + I₂ (aq)--->  CH₃COCH₂I(aq) + H⁺(aq) + I^- (aq)
Note: reaction uses an acid catalyst.

[Astrokel]

Perhaps you would want to look at its mechanism on the rate determining step.

[tash]

Sorry but what do you mean?

[Astrokel]

Do you know what does rate law tells you about the mechanism?

Look at the mechanism: http://www.chemie.uni-regensburg.de/Organische_Chemie/Didaktik/Keusch/chembox_jod_acet-e.htm

[tash]

well I read somewhere that the rate law for a multi-step reaction is always equal to the slowest of the steps.

So...In this reaction, the reason for why iodine doesn't effect the reaction rate is because it isn't involved in the slowest step???

[macman104]

Yup!

[tash]

haha, yay!

Thanks for all your help