On heating lead nitrate, the evolution of a brown gas confirms the formation of which gas?
Answer and explanation
Correct answer: Nitrogen dioxide
Lead nitrate undergoes thermal decomposition: \(2\mathrm{Pb(NO_3)_2} \xrightarrow{\Delta} 2\mathrm{PbO} + 4\mathrm{NO_2} + \mathrm{O_2}\). \(\mathrm{NO_2}\) is a brown gas, so the brown fumes confirm the formation of nitrogen dioxide. Although \(\mathrm{O_2}\) is also produced, it is colourless and therefore does not account for the brown colour.
Frequently asked questions
What is the correct answer to this question?
Nitrogen dioxide
Why is this the correct answer?
Lead nitrate undergoes thermal decomposition: \(2\mathrm{Pb(NO_3)_2} \xrightarrow{\Delta} 2\mathrm{PbO} + 4\mathrm{NO_2} + \mathrm{O_2}\). \(\mathrm{NO_2}\) is a brown gas, so the brown fumes confirm the formation of nitrogen dioxide. Although \(\mathrm{O_2}\) is also produced, it is colourless and therefore does not account for the brown colour.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
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