Here's the balanced chemical equation for the reaction:
2KI(aq) + Br₂(l) → 2KBr(aq) + I₂(s)
Explanation:
* Potassium iodide (KI) is a soluble ionic compound, meaning it exists as potassium (K⁺) and iodide (I⁻) ions in solution.
* Bromine (Br₂) is a diatomic liquid element.
* Potassium bromide (KBr) is also a soluble ionic compound, forming potassium (K⁺) and bromide (Br⁻) ions in solution.
* Iodine (I₂) is a solid element.
Mechanism:
The reaction occurs because bromine is more reactive than iodine. When bromine is added to a solution of potassium iodide, bromine atoms displace iodide ions from the potassium iodide solution, forming bromide ions and elemental iodine.
Observations:
* Color Change: The solution initially appears colorless or light yellow. As the reaction proceeds, a dark brown color emerges due to the formation of elemental iodine.
* Solid Formation: If the reaction mixture is concentrated enough, solid iodine will precipitate out of solution.
Important Note:
This reaction is a common demonstration of the relative reactivity of halogens. Bromine is more reactive than iodine, and the reaction results in the formation of a less reactive halogen (iodine) and a salt (potassium bromide).
