Dinitrogen and dioxygen are main constituents of air but these do not react with each other to form oxide of nitrogen because `"…….."`.

Options

A. the reaction is endothemic and requires very high temperature
B. the reaction can be initiated only in presence of a catalyst
C. oxides of nitrogen are unstable
D. `N_(2)` and `O_(2)` are unreactive

Explanation

**Step-by-Step Solution:**

1. **Identify the Reactants**: The main constituents of air are dinitrogen (N2) and dioxygen (O2).

2. **Understand the Nature of Bonds**: Dinitrogen has a triple bond (N≡N) and dioxygen has a double bond (O=O). These bonds are strong and stable.

3. **Bond Breaking Requirement**: For N2 and O2 to react and form nitrogen oxides, the strong bonds in both molecules must be broken. This requires a significant amount of energy.

4. **Stability of Nitrogen**: Nitrogen is a very stable element due to its strong triple bond. This stability makes nitrogen relatively inert under normal conditions.

5. **Energy Consideration**: The reaction between N2 and O2 is highly endothermic, meaning it absorbs heat. This reaction requires a high amount of energy (bond dissociation energy) to break the bonds.

6. **Atmospheric Conditions**: The normal atmospheric conditions do not provide sufficient energy (high temperature) to overcome the bond dissociation energy needed for the reaction to occur.

7. **Conclusion**: Therefore, dinitrogen and dioxygen do not react with each other to form nitrogen oxides under normal atmospheric conditions because the reaction is endothermic and requires very high temperatures.

**Final Answer**: Dinitrogen and dioxygen do not react with each other to form oxides of nitrogen because the reaction is endothermic and requires very high temperatures that are not available in the atmosphere.

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