Lead Iodide Precipitation

When aqueous lead(II) nitrate reacts with aqueous potassium iodide, a double displacement reaction occurs. Potassium nitrate remains dissolved, while lead(II) iodide precipitates as a bright yellow solid.

1. Dissolve lead(II) nitrate in water to form a clear solution.
2. Dissolve potassium iodide in a separate container of water.
3. Mix the two solutions together.
4. Observe the immediate formation of a bright yellow precipitate of lead(II) iodide.

Lead Nitrate and Potassium Iodide - Chemistry and Biochemistry Demo lab at OSU:

📄 What happens when lead nitrate reacts with potassium iodide - Unacademy: https://unacademy.com/content/question-answer/chemistry/what-happens-when-lead-nitrate-reacts-with-potassium-iodide/

• Compare the reaction at room temperature with the heated and cooled version (Golden Rain).
• Vary concentrations to see how the intensity of the precipitate changes.
• Demonstrate other double displacement reactions (e.g., silver nitrate with sodium chloride) for comparison.

• Lead salts are highly toxic — avoid ingestion, inhalation, or skin contact.
• Always wear safety glasses, gloves, and a lab coat.
• Do not dispose of lead-containing waste down the drain; collect and store as hazardous waste.

• What type of reaction occurs between lead nitrate and potassium iodide? (Double displacement, also called metathesis.)
• Why does a precipitate form immediately? (PbI₂ is insoluble in cold water, unlike KNO₃ which remains dissolved.)
• What color is the precipitate and why? (Yellow, due to the properties of lead(II) iodide crystals.)
• How does heating the solution change the result? (PbI₂ dissolves in hot water and recrystallizes as golden flakes upon cooling.)
• What real-world hazards are associated with lead compounds? (They are toxic and environmentally harmful.)