I don't have a sufficient amount of potassium iodide, so I wanted to know if there is other way which I can use to dissolve iodine without using potassium iodide.

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    $\begingroup$ It depends on the use of the solution afterwards $\endgroup$ – Alchimista Jan 2 '20 at 8:30
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    $\begingroup$ Dissolving in what solvent? Are you constrained to use only water? $\endgroup$ – matt_black Jan 2 '20 at 15:49

Aside of dissolving iodine in ethanol, suggested in the other answer, another way is to reduce a part of iodine to iodide, e.g. by the classical reaction with thiosulphate. The rest of iodine will dissolve.

The needed amount of thiosulphate is at least 1/3 of the stoichiometric amount wrt the total iodine.

$$\ce{2 S2O3^2- + I2 -> S4O6^2- + 2 I-}$$

$$\ce{I- + I2 -> I3-}$$

As 2 mols of thiosulphate reacts with 1 mol of molecular iodine, there is needed at least 2 mol of thiosulphate per 3 mols of iodine.

$$\ce{2 Na2S2O3 + 3 I2 -> Na2S4O6 + 2 NaI3}$$

Or, if the target concentration is low enough, iodine need not iodide to dissolve itself in water.


Elemental iodine is slightly soluble in water, with one gram dissolving in 3450 ml at 20 °C and 1280 ml at 50 °C


Dissolve it in ethanol. Iodine I2 dissolves in ethanol to give a very well known solution sometimes called "tincture of iodine"1

  • $\begingroup$ I think prior to posting the answer it would be better to first ask OP in the comments whether changing the solvent would be a viable option for them. From the context it appears they want to use aqueous solution. Also, please don't forget to end the sentences with a full-stop (or other applicable punctuation marks depending on the situation). $\endgroup$ – andselisk Jan 2 '20 at 10:02
  • $\begingroup$ HE SAID WITHOUT KI, doesnt that imply change? $\endgroup$ – Haha Hahaha Jan 2 '20 at 13:44
  • $\begingroup$ No, it doesn't. Please don't CAPS at anyone, this isn't polite. $\endgroup$ – andselisk Jan 2 '20 at 13:50
  • $\begingroup$ Okay @andselisk im sorry, just curious, what does it mean then, does he want to dissolve it in lesser KI or what? $\endgroup$ – Haha Hahaha Jan 2 '20 at 13:51
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    $\begingroup$ Oh okay, thanks a lot, understood! $\endgroup$ – Haha Hahaha Jan 2 '20 at 13:54

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