3 I₂ (s) + 6 NaOH (aq) → 5 NaI (aq) + NaIO₃ (aq) + 3 H₂O (l)
Explanation:
* Reactants: Iodine (I₂) is a solid, and sodium hydroxide (NaOH) is an aqueous solution.
* Products:
* Sodium iodide (NaI) is formed as a result of the reduction of iodine.
* Sodium iodate (NaIO₃) is formed as a result of the oxidation of iodine.
* Water (H₂O) is also produced.
Here's how the reaction works:
1. Disproportionation: Iodine (I₂) is both oxidized and reduced.
* Oxidation: Some iodine atoms lose electrons and become iodate ions (IO₃⁻).
* Reduction: Other iodine atoms gain electrons and become iodide ions (I⁻).
2. Reaction with NaOH: The iodide ions react with sodium hydroxide to form sodium iodide (NaI) and water. The iodate ions also react with sodium hydroxide to form sodium iodate (NaIO₃) and water.
Important Notes:
* The reaction is usually carried out in a hot solution to speed up the process.
* The reaction produces a yellow solution due to the formation of triiodide ions (I₃⁻).
* This reaction is often used to prepare sodium iodate, which is used in various applications, including as a reagent in analytical chemistry.