Out of the seven oxides of Nitrogen (N₂ O, NO, NO₂ , NO₃ , N₂O₃ , N₂ O₄ , N₂O₅ ) which are associated with combustion and are classified as pollutants?
- ANO, NO₂Correct
- BN₂O, NO, NO₂ , NO₃
- CN₂O₃ , N₂ O₄ , N₂O₅
- DNO₃ , N₂ O₃ , N₂ O₄
Solution
Concept
NOx pollutants from combustion are NO and NO₂.
Formula
N₂ + O₂ → 2NO (at high temperature); 2NO + O₂ → 2NO₂
Step-by-step solution
1. Combustion at high temperature forms NO from N₂ and O₂. 2. NO oxidizes in air to NO₂. 3. NO and NO₂ together are called NOx. 4. These two are the classified air pollutants.
Explanation
Combustion mainly produces NO and a little NO₂. Together they are called NOx and are the regulated pollutants. N₂O is a greenhouse gas, and the other oxides are unstable or rare in air.
Why the other options are wrong
B: N₂O and NO₃ are not the main combustion pollutants. C: N₂O₃ , N₂ O₄ , N₂O₅ are unstable or minor. D: Same reason, these are minor species.
Shortcut
NOx = NO + NO₂.
Common mistake
Including N₂O (laughing gas) in NOx pollutants.
Correct answer: A) NO, NO₂