Iodine clock reaction-equation?

hey, does anyone know the equation for iodine clock reaction? ive searched the internet but i think my reactants are slightly different to the normal ones

I used:
Potassium peroxydisulfate
Potassium iodide
sodium thiosulphate
starch solution

but thats all i can tell you because i dont even know the products! im having a really blank day.....

if anyone could help i would really appreciate it thankyou!

Reply 1

Kolya

First the iodide ions react with the peroxydisulfate ions to produce iodine:

2I^- + S_2O_8 \ ^{2-} \rightarrow I_2 + 2SO_4 \ ^{2-}

, but then the iodine is turned back into iodide ions by the sodium thiosulfate:

I_2 + 2S_2O_3 \ ^{2-} \rightarrow 2I^- + S_4O_6 \ ^{2-}

. Once the thiosulfate runs out, the

I_2

iodine then reacts with the starch and turns the solution a dark blue/black colour.

Reply 2

nikki14

Kolya

First the iodide ions react with the peroxydisulfate ions to produce iodine:

2I^- + S_2O_8 \ ^{2-} \rightarrow I_2 + 2SO_4 \ ^{2-}

, but then the iodine is turned back into iodide ions by the sodium thiosulfate:

I_2 + 2S_2O_3 \ ^{2-} \rightarrow 2I^- + S_4O_6 \ ^{2-}

. Once the thiosulfate runs out, the

I_2

iodine then reacts with the starch and turns the solution a dark blue/black colour.

thankyou thankyou thankyou!

Reply 3

samara123

I am doing my chemistry coursework and used the same chemicals, is the equation above definitely correct?
I used starch solution
Potassium iodide
Potassium peroxidisulfate
sodium thiosulfate

When I looked online many people have done the iodine clock reaction differently.....