Interesting development in this.
After the oxidation of 0.1g KI in 10ml H2O using 10ml 0.6M H2O2 at pH~2, which is essentially over in 20mins as per above, I had what must have been
about 80mg iodine precipitated and above it 20ml of almost clear water - confirming concentration of iodide remaining in solution was tiny, as else
the iodine would have dissolved.
And so this remained for about 2 weeks.
Today I was surprised to see the iodine entirely gone and the solution completely clear.
The only reaction I can think possible is further oxidation of I2 to the 5+ state KIO3 by the H2O2. But why such a sudden onset of reaction, with
then proceeds to completion? The only explanation is that its autocatalytic. However all references Ive seen mention it only first order in [I2]
rate = k[I2]
There must be a lot more to it than that. |