A iodometric titration calculation?

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1 g of KIO3{potassium iodate} is dissolved in water to gives a 250.00 cm^3 solution. 25.00cm^3 of potassium iodate is pippeted into a conical flask and add about 1.00cm^3 of ...show more
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I tend to believe what you mean by "potassium iodine" is actually "potassium iodide". So the two reactions are:
KIO3 + 5KI + 3H2SO4 → 3K2SO4 + 3I2 + 3H2O
2Na2S2O3(aq) + I2(aq) → Na2S4O6(aq) + 2 NaI(aq)
As you stated in the question title, the second reaction is called iodometry. In the reaction, the thiosulfate anion reacts stoichiometrically with iodine, reducing it to iodide as it is oxidized to tetrathionate.
You are right, we can not find the number of mole of sodium thiosulphate without knowing its concentration.
Starch solution should be freshly prepared, since an old solution may be deteriorated by bacteria, thus may not work as required.
Potassium iodide slowly turns yellow on standing in air, due to the oxidation of the negative iodide ions by dissolved oxygen to iodine.

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wow...thanks of your ans
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