Nitric acid is produced commercially by the Ostwald process. The three steps of the Ostwald process are shown in the following equations.

Nitric acid is produced commercially by the Ostwald process. The three steps of the Ostwald process are shown in the following equations.4 NH3(g) + 5 O2(g) -> 4 NO(g) + 6 H2O(g)2 NO(g) + O2(g) -> 2 NO2(g)3 NO2(g) + H2O(l) -> 2 HNO3(aq) + NO(g)What mass of NH3 must be used to produce 1×10^6 kg HNO3 by the Ostwald process, assuming 90% yield in each reaction?