We’re being asked to explain what factor leads to the decrease in entropy of the reaction:
2 NO(g) + O2(g) → 2 NO2(g)
Recall that entropy is the degree of chaos or disorder of a system and that it depends on the following:
Entropy decreases when NO(g) is oxidized by O2(g) to NO2(g).
What major factor leads to a decrease in entropy as the reaction shown takes place?