Question

${\text{2Pb(NO}}_3{)}_2\text{(s)}\stackrel{\text{Heat}}{\to }2\text{PbO(s)}+4{\text{NO}}_2\text{(g)}+{\text{O}}_2\text{(g)}$

The reaction given above is example of:

• A. combination reaction
• B. decomposition reaction
• C. endothermic reaction
• D. exothermic reaction

Answer 1

Answer: (B), (C)

The correct options are
B decomposition reaction
C endothermic reaction

In the given reaction, the single compound lead nitrate $\left({\text{Pb(NO}}_3{)}_2\right)$ on heating is breaking down to form lead oxide $\left(\text{PbO}\right)$, nitrogen dioxide ${\text{(NO}}_2)$, and oxygen ${\text{(O}}_2)$. Such reactions in which one compound breaks down to form two or more compounds on heating is known as a decomposition reaction.
As heat is absorbed by the compound thus it is also an example of endothermic reaction. In other words, we can also say that it is a thermal decomposition reaction. So both decomposition & endothermic are correct.