The effect of concentration on the rate of a homogenous reaction I have to do an experiment where I will find out what the influence of the concentration on the rate of a homogenous reaction is.
We are asked to create 2 solutions, respectively A and B:
$$\ce{KI + Na2S2O3 + Starch + water}$$
and
$$\ce{H2O2 + H2SO4 + water}$$
As long as A and B aren't added together, the reaction cannot start.
Now what I'm supposed to do is make 10 different A and B solutions and add these together and measure the time it takes for the solution to turn blue (Iodine + Starch as an indicator).

Now, my problem is that the following questions are also asked:
&quot;Write down the different reactions that take place&quot;
This seems dubious to me but might not be.
e.g. Does dissolving into ions also count as a reaction?
Does the Starch (for which I have no given chemical formula) react in solution A?
I've also read online that adding $\ce{H2O2}$ and $\ce{H2SO4}$ creates a &quot;Piranha&quot; solution ($\ce{H3O+ + HSO4- + O}$ or $\ce{H2SO5 + H2O}$, I've found both online but I don't know which is correct here.)
In conclusion I just don't know which reactions I should give (Everything that happens in A and B isolated from eachother or everything that happens when I add A and B together? Either way, I'm also not sure what the reactions would be because, for instance, I don't have any certainty on what the chemical composition of the Starch is.)
Is the reaction a multistep reaction or a single step reaction? Why? If it's a multistep reaction, write down the partial reactions
Assuming that adding B to A is &quot;The&quot; reaction, how do I find out if there are multiple steps or not? How do I find these steps?
Given that this question is asked already makes me think that it is in fact a multi-step reaction.
I've also read online that adding $\ce{H2O2}$ and $\ce{H2SO4}$ creates a &quot;Piranha&quot; solution [...]

This is true - in principle. In reality, Piranha solution is made from concentrated sulfuric acid and 30% hydrogen peroxide.
In the case of your experminent, you will most likely use diluted sulfuric acid and aqueous solutions of hydrogen peroxide with a much lower concentration. Consequently, the Piranha effect will not play a role in your experiment, neither is the oxidizing power of sulfuric acid relevant here.
On a side side note, treating a sample with conc. $\ce{H2SO4}$ is a method for the qualitative determination of iodide: Upon heating, one can observe the violet vapour of iodine.
In your case, you need the sulfuric acid to keep the pH value low. Under these conditions, $\ce{H2O2}$ acts as an oxidant:
$$\ce{H2O2 + 2 H+ + 2 e- -&gt; 2 H2O}$$

Does dissolving into ions also count as a reaction?

No.

Does the Starch (for which I have no given chemical formula) react in solution A?

Starch is a mixture of two natural polymers (amylopectin and amylose), both made from D-glucose. Amylopectin doesn't play a role here, but it doesn't disturb either and it's just cheaper to let you work with the natural mixture.
It's the helical amylose that is relevant here - and it acts as a reagent.
What actually happens in the reaction is the following:
$$\ce{2 I- -&gt; I2 + 2 e-}$$
$$\ce{I2 + I- -&gt; I3-}$$
The linear triodide ion forms a strongly coloured inclusion complex with the amylose in the starch.