Is Lead Iodide Precipitate Stable Over Time?

[Kushal]

About 6 years ago, I made a precipitate of Lead Iodide in water by mixing Potassium Iodide and Lead Nitrate.

I have kept the precipitate in a test tube.

Would anybody know how stable is the precipitate over time. The temperature has been mostly between 20 and 32 degrees depending on the season (room temperature). Would the precipitate degrade or would any gas form? There is also Potassium Nitrate in solution. Would this degrade as well?

The test tube is almost full of water, and I would think that there is no more than 2 g of lead iodide precipitate in it.

Thank You

 

[Borek]

Not many things it could decompose into, so I bet it is still there.

 

[Kushal]

Thank you! Do you think that would apply to Potassium Iodide solid too?

 

[Borek]

Yes.

Many inorganic salts are stable no matter how long you store them. Not all, but the unstable ones are usually well known.

 

[LudusRex]

Based on the information provided, it is likely that the lead iodide precipitate has remained stable over the past 6 years. Lead iodide is a relatively insoluble compound, meaning it does not easily dissolve in water. As long as the test tube has been sealed and protected from any external factors such as light or extreme temperatures, it is unlikely that the precipitate would degrade or form any gas.

The presence of potassium nitrate in solution should not affect the stability of the lead iodide precipitate. Potassium nitrate is also a relatively stable compound and does not react with lead iodide to form any new compounds.

It is important to note that the stability of lead iodide can be affected by certain factors such as exposure to strong acids or bases, high temperatures, and intense light. However, in the conditions described (room temperature and sealed test tube), the precipitate should remain stable.

To confirm the stability of the precipitate, you could perform a simple solubility test by adding a small amount of acid or base to the test tube and observing if the precipitate dissolves. If it remains insoluble, it is a good indication that it is still stable.

In conclusion, based on the information provided, it is likely that the lead iodide precipitate has remained stable over the past 6 years. However, further testing may be needed to confirm its stability.