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Some reactions involving iodine/iodide. Oxidation of iodide. Potassium iodide solution (right) is colourless. Here we are about to oxidise the iodide using orange bromine water. The orange colour of the bromine changes to the darker brown colour of iodine, I 2.
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Oxidation of iodide Potassium iodide solution (right) is colourless. Here we are about to oxidise the iodide using orange bromine water.
The orange colour of the bromine changes to the darker brown colour of iodine, I2.
The brown colour of iodine in iodide is clearly seen in this beaker. Br2 + 2e- → 2Br- 2I- → I2 + 2e- Br2 + 2I- → 2Br- + I2 I2 + I- → I3-
Reduction of iodine Iodine is a mild oxidising agent.
Colourless sodium thiosulfate solution will be used to reduce iodine to iodide.
As the thiosulfate solution is added, the brown colour begins to fade.
The final solution is completely colourless. I2 + 2e-→ 2I- 2S2O32- → S4O62- + 2e- I2 + 2S2O32- → 2I- + S4O62-