An explanation for such observation?

Question

After putting starch in the solution for 10 mins, where it should normally change into a deep-blue colour with thiiodide, it does not. Why might it not change colour? Thanks for your explanation.

I was thinking of maybe there was enough of the reactants, and so there is no colour change, but then there should be at least some colour change (maybe to a faint blue). I'm not sure anymore.

Answer 1

First of all I guess you mean triiodide (I3(-)) ions and not thiiodide.
When you mix starch and I3(-) you should see a blue colour.
You're not providing enough details of the experiment for us to understand what happened help you.