Dinitrogen is a robust compound, but reacts at high altitudes to form oxides. The oxide of nitrogen that can damage plant leaves and retard photosynthesis is :

Solution

Chemistry ma’am · 4 steps

Follow the chain N₂ → NO → NO₂: the last one, NO₂, is what hurts the leaves.

1. Forming NO. At high altitudes, during lightning and inside hot engines, the temperature is high enough to break the strong N≡N bond. Dinitrogen then combines with oxygen: N₂ + O₂ → 2NO.
2. NO to NO2. NO does not stay for long. It reacts quickly with oxygen, 2NO + O₂ → 2NO₂, and with ozone, NO + O₃ → NO₂ + O₂.
3. Effect on plants. At higher concentrations, NO₂ damages plant leaves and slows down photosynthesis. In humans it irritates the lungs and can cause acute respiratory disease in children.
4. So. The oxide that damages leaves and retards photosynthesis is NO₂, option (c).

The idea to keep. For nitrogen oxide pollution, remember the chain N₂ → NO → NO₂. The brown gas NO₂ at the end is the one that harms leaves and irritates lungs.

Answer from the NTA final answer key. Solution by PrepWiser.