Question

Dinitrogen and dioxygen, the main constituents of air do not react with each other in atmosphere to form oxides of nitrogen because

• A. N₂ is unreactive in the condition of atmosphere
• B. Oxides of nitrogen are unstable
• C. Reaction between them can occur in the presence of a catalyst
• D. The reaction is endothermic and require very high temperature

Answer 1

The Correct Option is D

Dinitrogen (N₂) and dioxygen (O₂) are the primary components of the Earth's atmosphere. Although both elements are quite abundant, they do not readily react with each other to form nitrogen oxides (NO_x) because:

1. N₂ is unreactive under normal atmospheric conditions: Nitrogen molecules have a triple bond (N≡N) that is very strong and requires a significant amount of energy to break. This makes N₂ relatively inert at the lower temperatures typically found in the atmosphere.
2. The reaction is endothermic and requires very high temperatures: The reaction between N₂ and O₂ to form nitrogen oxides is endothermic, meaning it absorbs energy. This requires very high temperatures, such as those found during lightning strikes or in internal combustion engines, to provide the necessary activation energy.

The correct answer to the question is that the reaction between dinitrogen and dioxygen is endothermic and requires very high temperatures, making the option "The reaction is endothermic and require very high temperature" the right choice.

In conclusion, the high energy barrier due to the strong triple bond in nitrogen molecules and the endothermic nature of the reaction prevent these two gases from reacting under normal atmospheric conditions.