About It
It was invented by a German / Latvian Chemist by the name of Willhelm Ostwald. Implemented in 1908 and Patented in 1909. Prior to this process, Nitric Acid was produced by distilling saltpeter (Sodium Nitrate NaNO3 or Potasium Nitrate KNO3) with concentrated sulfuric acid.
The Ostwald Process now accounts for all inductrial production of Nitric Acid; which is crucial to Fertilizers and Explosives.
Since each step in the Ostwald Process is Exothermic, increasing the temperature anywhere along the line will shift any equilibrium to the left, reducing the yield; according to Le Châtelier’s principle. In addition to that, adding more pressure or decreasing the volume will also favor forward reaction because the product has less gas molecule than the reactant.
It is important to note that the optimum yield occurs when the temperature is around 1,000 C. There must be sufficient energy to provide adequate "activation energy", yet not so high that it would shift the various reactions to the left, reducing yield.
The first and third reaction would seem to favor a lower pressure but there would not be a great advantage. Some product removal would help more. In part a pressure change would have little effect as the volumes are identical. The pressure and the temperatures are quite high as in the Haber process where the pressure is 200 atms, and the temperature is around 500oC. There is one big problem in the cost of the catalysts used, made of a fine screen of rhodium and platinum must be used. Besides being expensive the plant has to be shut down to clean and repair them. The NO (g) from part 3 is also reused in part 3. There is also a great danger of explosions when NH3 and nitrate are concerned; like the blast that killed 500 people in Texas in 1947.
There is a catalyst in the Ostwald process. It is because in the Industries which manufacture Nitric Acid, the chemist tries to speed up the rate of the reaction to meet the needs and demand of the Nitric Acid. They don’t need chemical reactions which will proceed many days or months without running into completion.
There are more factors then just catalysts, like pressure, surface area, temperature, and the nature of the gasses.
In the transition state; the catalyst absorbs the atoms of the reacting substances towards its surface and this makes them unstable and can, therefore, react.