Air contain about 99% of `N_(2)` and `O_(2)` gases. Why do not they combine to form NO under the standard conditions? Standard Gibbs energy of formation of `NO(g)` is `86.7 kJ mol^(-1)`.

Explanation

To understand why nitrogen (N₂) and oxygen (O₂) do not combine to form nitric oxide (NO) under standard conditions, we can analyze the reaction using thermodynamic principles, particularly the concept of Gibbs free energy.

### Step-by-Step Solution:

1. **Identify the Reaction**: The reaction we are considering is:
\[ N_2(g) + \frac{1}{2} O_2(g) \rightarrow NO(g) \]
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