Here's why:
* Double displacement reactions involve the exchange of ions between two reactants. In this case, the lead(II) ions (Pb²⁺) from lead(II) nitrate combine with the iodide ions (I⁻) from potassium iodide to form lead(II) iodide (PbI₂), which is a yellow precipitate.
* The remaining ions, potassium (K⁺) and nitrate (NO₃⁻), also combine to form potassium nitrate (KNO₃), which remains dissolved in solution.
The balanced chemical equation for this reaction is:
Pb(NO₃)₂ (aq) + 2 KI (aq) → PbI₂ (s) + 2 KNO₃ (aq)
Here's a breakdown:
* Reactants: Lead(II) nitrate (Pb(NO₃)₂) and potassium iodide (KI) are both aqueous solutions (aq).
* Products: Lead(II) iodide (PbI₂) is a yellow solid precipitate (s), while potassium nitrate (KNO₃) remains in solution (aq).
This reaction is also considered a precipitation reaction because the formation of the insoluble lead(II) iodide causes it to precipitate out of the solution.
