While heating lead nitrate, a student identified the evolved brown gas as oxygen. What is the correct correction to the student's statement?
Answer and explanation
Correct answer: The brown gas is NO₂, and O₂ is colourless
On heating, lead nitrate decomposes according to 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂. Nitrogen dioxide (NO₂) is a brown gas, whereas oxygen (O₂) is colourless. Therefore, the student confused the two gaseous products, and option A gives the correct correction. The other statements reverse or misidentify their colours and formulas.
Frequently asked questions
What is the correct answer to this question?
The brown gas is NO₂, and O₂ is colourless
Why is this the correct answer?
On heating, lead nitrate decomposes according to 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂. Nitrogen dioxide (NO₂) is a brown gas, whereas oxygen (O₂) is colourless. Therefore, the student confused the two gaseous products, and option A gives the correct correction. The other statements reverse or misidentify their colours and formulas.
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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