A \( \text{SO}_2(\text{g}) + \text{NO}_2(\text{g}) \leftrightharpoons \text{SO}_3(\text{g}) + \text{NO}(\text{g}) \)
B \( \text{H}_2(\text{g}) + \text{I}_2(\text{g}) \leftrightharpoons 2\text{HI}(\text{g}) \)
C \( 2\text{NO}_2(\text{g}) \leftrightharpoons \text{N}_2(\text{g}) + \text{O}_2(\text{g}) \)
D \( \text{N}_2\text{O}_4(\text{g}) \leftrightharpoons 2\text{NO}_2(\text{g}) \)