[soerenskov88]

Hi…

I have been doing some research about how different types of radiation react with a solution of kaliumpermanganese (KMnO4).

Is measure how much [MnO4-] there is left, as function of time… In a time, concentration graph.
I know that the reason for MnO4- changes, is that it change into MnO2 (“Brownstone”).

I have exposed my solution with sunlight (slow process still measuring), gamma radiation and I have put my solution in a neutron source. The first is in a small flask, and the others in small test tubes.

I am not finish with my sunlight experiment, but with gamma and in the neutron source.

In both cases I start with a concentration on 1,6M.

In the case with gamma, after a half an hour the concentration goes down to about 1,0M and then it is constant for several hours, and after 5 hours the concentration is 0,9M in other word almost constant.

This repeats itself in the neutron source, almost… After half an hour the concentration goes from 1,6M to 0,24M and after 1 and 2 days the concentration is still about 0,2M…

So what do you think? Is it because the MnO2 creates a sort of layer in the outskirt of the test tube ? So the radiation cannot “get in” and react with MnO4- ?

I would be delighted if anyone could give me an idea or tell what to investigate..

Greeting Søren Skov, Denmark.

[Bakegaku]

Well first I'd suggest having a control sample that isn't subject to any radiation, and that you be sure that  apart from the types of radiation all variables, such as temperature, concentration and sample size, are kept the same to prevent skewing results. 

Other than that, there's not really enough information to conclude that it is the MnO₂ that is blocking the radiation.  I'd test this hypothesis by testing how much radiation is able to go through such a thickness of MO₂.  If those results turn up positive then I'd suggest postulating a mechanism by which the neutrons convert MnO₄^- into MnO₂.