Chapter 18, Problem 51E

The equilibrium between nitrogen monoxide, oxygen, and nitrogen dioxide may be expressed in the equation $\text{2 NO}\left(\text{g}\right)+{\text{O}}_{\text{2}}\left(\text{g}\right)\rightleftharpoons \text{2 NO}\left(\text{g}\right)$. Write the equilibrium constant expression for this equation. Then express the same equilibrium in at least two other ways, and write the equilibrium constant expression for each. Are the constants numerically equal? Cite some evidence to support your answer.

Nitrogen monoxide and oxygen, both colorless gases, react to form reddish-brown nitrogen dioxide.