Lead sulphite decomposes to
Answers
Thermal decomposition is the breaking down of a compound into simpler substances using heat. However, some metal compounds do not break down into the pure metal under thermal decomposition.
To get the pure metal, a reduction reaction must occur, i.e. a reaction in which there is loss of oxygen, gain of electrons, or gain of hydrogen. A reducing agent, such as hydrogen gas, can be used to liberate some metals from simple compounds.
Demonstration Instructions
This model begins with water and universal indicator solution in the test tube, and 50 g of lead sulfide in the gas tube.
Turn on the Bunsen burner by moving the slider bar up. Depress the left-hand mouse button on the slider bar, hold it down and move the bar upwards, release the mouse button.
Play the simulation. Click on the pause button in the main toolbar.
Observe the change in pH of water in the test tube.
Wait until all of the lead sulfide has thermally decomposed, by monitoring the reaction details window associated with the gas tube. To open the reaction details, hold the mouse over the gas tube and click on the light blue "i" icon.
To reduce the lead oxide (product of thermal decomposition) leave the Bunsen burner on and turn on the hydrogen. Depress the left-hand mouse button on the slider bar, hold it down and move the bar upwards, release the mouse button. Again, look at the reaction details to see that lead is produced.
