UPSC CDS 2 2020 GK Paper

Concept:Thermal decomposition of lead nitrate produces lead oxide, nitrogen dioxide, and oxygen.Explanation:When lead nitrate ($\mathrm{Pb(NO_3)_2}$) is strongly heated, it decomposes.The balanced chemical equation is:$2\mathrm{Pb(NO_3)_2} \xrightarrow{\Delta} 2\mathrm{PbO} + 4\mathrm{NO_2} + \mathrm{O_2}$The products are a yellow residue of lead oxide ($\mathrm{PbO}$), a brown gas of nitrogen dioxide ($\mathrm{NO_2}$), and oxygen ($\mathrm{O_2}$).Among the given options, only option B lists $\mathrm{PbO}$ and $\mathrm{NO_2}$, which are the main solid and gas products.Note that oxygen is also formed, but it is not listed in the options.Answer:B. $\mathrm{PbO}$ and $\mathrm{NO_2}$ (oxygen is also produced).