2. As is positive for the reaction OA) A) 2H2(g) + O2(g) → 2H₂O(g) 2NO2(g) → N2O4(8) B) c) 2Hg(1) + O2(g) → 2HgO(s) C) D) CO2(g) → CO₂(s) OD) OE) BaF2(s) → Ba²+(aq) + 2F¯(aq)