View source for Golden rain demonstration

{{multiple images
 |header=Reversible formation of "golden rain"
 |image1=Golden rain demonstration.jpg|caption1=At room temperature
 |image2=Golden rain demonstration5.jpg|caption2=When heated
}}

'''Golden rain demonstration''' is made by combining two colorless solutions, [[potassium iodide]] solution and [[Lead(II) nitrate]] solution at room temperature to form yellow [[precipitate]]. During the chemical reaction, golden particles gently drop from the top of [[Erlenmeyer flask]] to the bottom, similar to watching the rain through a window. The golden rain chemical reaction demonstrates the formation of a solid [[precipitate]]. The golden rain experiment involves two soluble ionic compounds, [[potassium iodide]] (KI) and [[lead(II) nitrate]] (Pb(NO<sub>3</sub>)<sub>2</sub>). They are initially dissolved in separate water solutions, which are each colorless. When mixed, as the lead from one solution and the iodide from the other combine to form [[lead(II) iodide]] (PbI<sub>2</sub>), which is [[insoluble]] at low temperature and has a bright golden-yellow color. Although this is a reaction solely of the dissociated ions in solution, it is sometimes referred to as a [[double displacement reaction]]:<ref>{{Cite web|url=http://www.compoundchem.com/2015/04/23/golden-rain/|title=Chemical Reactions: Lead Iodide & 'Golden Rain'|date=23 April 2015}}</ref>

:Pb(NO<sub>3</sub>)<sub>2</sub> + 2 KI → 2 KNO<sub>3</sub> + PbI<sub>2</sub>

At higher temperature, this substance easily re-dissolves by [[Dissociation (chemistry)|dissociation]] to its colorless ions. The actual change ([[net ionic equation]]) is thus:

:<math chem>\underbrace\ce{ {Pb^{2+}_{(aq)}} + 2I^-_{(aq)} }_\text{colorless solution} \ce{<=>} \underbrace\ce{ PbI_{2(s)} }_\text{yellow precipitate}</math>

== References ==
<references/>

== External links ==
* [https://www.youtube.com/watch?v=zJkv0HiqApo Golden rain - ionic bonding] Royal Society of Chemistry

[[Category:Chemistry classroom experiments]]