Question

Air contains about 99% N₂ and O₂ gases. Why do not these gases combine to form NO molecule under the standard conditions? Standard Gibbs energy of formation of NO(g) is 86.7 kJ mol^-1.

Answer 1

Since the standard Gibbs energy of formation is +ve for the combination of N₂ and O₂ to form NO. So, this reaction is non-spontaneous under the standard conditions and so N₂ and O₂ do not combine to form NO.