What is the chemical identity of the solid residue obtained upon strongly heating lead nitrate?

The correct option is Lead(II) oxide.

Explanation

The question pertains to a thermal decomposition reaction. This is a category of chemical reactions where a single compound breaks down into two or more simpler substances when subjected to heat.

Analysis of the Reaction:
When lead nitrate is heated strongly, it undergoes decomposition. The reaction yields lead(II) oxide, nitrogen dioxide, and oxygen. The balanced chemical equation is:

2Pb(NO₃)₂ (s) $\xrightarrow{\text{Heat}}$ 2PbO (s) + 4NO₂ (g) + O₂ (g)

• Lead(II) oxide (PbO): This forms the solid residue. It is yellow in colour (often appearing reddish-yellow when hot and yellow when cold).
• Nitrogen dioxide (NO₂): This is observed as characteristic reddish-brown fumes emitted during the reaction.
• Oxygen (O₂): A colourless gas is also released.

Therefore, the chemical identity of the solid residue is Lead(II) oxide.

Key Takeaway:
The thermal decomposition of lead nitrate produces a yellow solid residue of Lead(II) oxide and evolves brown fumes of Nitrogen dioxide.