Why is it wrong to consider the brown gas in lead nitrate experiment as oxygen?
Answer and explanation
Correct answer: Oxygen is colourless and the brown gas is nitrogen dioxide
During heating, lead nitrate produces nitrogen dioxide, oxygen, and lead oxide: 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂. Nitrogen dioxide has a characteristic brown colour, whereas oxygen is a colourless gas. Therefore the brown fumes cannot be oxygen; they are nitrogen dioxide. Oxygen may also be produced, but its colourless appearance distinguishes it from the brown gas.
Frequently asked questions
What is the correct answer to this question?
Oxygen is colourless and the brown gas is nitrogen dioxide
Why is this the correct answer?
During heating, lead nitrate produces nitrogen dioxide, oxygen, and lead oxide: 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂. Nitrogen dioxide has a characteristic brown colour, whereas oxygen is a colourless gas. Therefore the brown fumes cannot be oxygen; they are nitrogen dioxide. Oxygen may also be produced, but its colourless appearance distinguishes it from the brown gas.
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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