The balanced chemical equation involved in manufacturing of HNO3 by Ostwald's process are shown as: Step 1 Formation of nitric oxide (NO) 4NH3( g)+5O2( g)Pt/Rh, gases- catalyst 500 K,9 bar 4NO(g)+6H2O Step 2 Formation of nitrogen dioxide (NO2) 2NO(g)+O2(g)→2NO2( g) Step 3 Absorption of NO2 (Formation of HNO3 ) 3NO2( g)+H2O→2HNO3(I)+NO(g)