I'm going to do an iodine clock reaction for a project and we had to submit the materials and safety sheets for the experiment a while ago. I thought I could do one by using hydrogen peroxide, sodium thiosulfate, potassium iodide and starch, but online I'm only seeing experiments that use sulfuric acid or another strong acid of some sort which is worrying me. I talked to my teacher and it's too late to change/add materials, so I'm really hoping that it can work? I'd also like to know what the strong acid does in the reaction, and what would happen (or wouldn't happen) without sulfuric acid?
Here's a bit from wikipedia for reference about the reaction:
This reaction starts from a solution of hydrogen peroxide with sulfuric acid. To this is added a solution containing potassium iodide, sodium thiosulfate, and starch. There are two reactions occurring in the solution.
(note: I didn't try formatting anything so the numbers after the ^ are the charges)
In the first, slow reaction, iodine is produced: H2O2 + 2I^− + 2H^+ → I2 + 2H2O
In the second, fast reaction, iodine is reconverted to 2 iodide ions by the thiosulfate: 2S2O3^2− + I2 → S4O6^2− + 2I^−
After some time the solution always changes color to a very dark blue, almost black. When the solutions are mixed, the second reaction causes the triiodide ion to be consumed much faster than it is generated, and only a small amount of triiodide is present in the dynamic equilibrium. Once the thiosulfate ion has been exhausted, this reaction stops and the blue colour caused by the triiodide – starch complex appears.