One step of the published mechanism
of the hydrogen peroxide iodine-clock
reaction is called into question by the result of an experimental
attempt (predicated on that mechanism) to integrate that reaction
into the elephant’s toothpaste demonstration to reveal and
control its iodine side product. Under conditions that were a hybrid
of those demonstrations (starch and thiosulfate added to the elephant’s
toothpaste demonstration), there was a pronounced induction period
preceding the appearance of both iodine and oxygen. This induction
period for both of these products indicated that
the reductant reacted not with iodine but with the transient intermediate,
hypoiodous acid (or hypoiodite), common to both iodine and oxygen
generation. Additional experiments based on the reaction of thiosulfate
with 8 times more moles of hypoiodite than moles of iodine supported
this conclusion.