A solid-solid reaction lead nitrate and potassium iodide

When two white solid substances are combined together the resulting mixture is yellow.

Scientific name: Lead nitrate reacts with potassium iodide producing potassium nitrate and lead iodide which is yellow.


Rates of Yellow (Lead Nitrate + Potassium Iodide)

by Jmu ChemDemos

Chemistry Reaction between solid KI and solid Lead (II) nitrate.wmv

by peter s p Lim


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Reaction formula

Pb(NO3)2 + 2KI → 2KNO3 + PbI2

Step-by-step instruction

  1. Prepare powdered potassium iodide and powdered lead nitrate. Both solids are white.
  2. Weight out equal amounts of both substances.
  3. Place the components into the jar and mix them together. For better mixing seal the jar with a cap and shake it for a while.
  4. The white powder turns yellow.
  5. You can repeat the experiment using some water. Pour some small amount of water into the jar before adding lead nitrate and potassium iodide. The color change takes place much more quickly.

Scientific background

When lead nitrate comes into contact with potassium iodide they reacts producing potassium nitrate and lead iodide. All substances in this reaction except lead iodide are white. The lead iodide is yellow. Since both the components are solid the reaction can proceed only on the surface of the crystals. The rate of the reaction is much slower in this case compared to the reaction in the presence of water since in the solutions particles are uniformly dispersed and it is easier for them to meet each other.


Published on 25 June 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst