In which of the following reactions can the oxidation number of the nitrogen be said to have increased?

A. 2NO(g) + O2(g) → 2NO2(g)
B. NO(g) + Cl2(g) → NOCl2(l)
C. FeSO4(aq) + NO(g) → Fe(NO)SO4(s)
D. NO(g) + Br2(l) → NOBr2(l)

Correct Answer:

Option A – 2NO(g) + O2(g) → 2NO2(g)