Question

Give a balanced chemical equation for each of the Catalytic oxidation of Ammonia.

Answer 1

Hint: Ostwald process is an industrial process which involves the catalytic oxidation of ammonia. In the Ostwald process, ammonia is made to react with oxygen and water in the presence of platinum catalyst to yield nitric acid.

Complete step by step solution:
The Ostwald process refers to a chemical process that converts ammonia into nitric acid ( $ HN{O_3} $ ) in two steps. In the first step, ammonia is oxidized leading to the formation of nitric oxide and nitrogen dioxide. The catalyst generally utilized in the Ostwald process is self-supporting platinum-rhodium catalyst gauzes for manufacturing of the nitrogen monoxide through the combustion of ammonia. And in the second step, nitrogen dioxide is absorbed in water. Thus, the first step of the Ostwald process is the catalytic oxidation of ammonia. The typical conditions for the process which contribute to an overall $ 98\% $ yield includes $ 4 - 10{\text{ }}atm $ (i.e. $ 410-1,000\;kPa $ ) and about $ 870-1,073\;K $ temperature.
The balanced chemical equations for the complete Ostwald process are written below:
$4N{H_3} + 5{O_{2\;}}\xrightarrow{{Pt}}4NO{\text{ + }}6{H_2}O{\text{ }} $
$ 2NO + {O_2} \to 2N{O_2} $
$ 2N{O_2} + {H_2}O \to HN{O_3} + HN{O_2} $

Additional information:
A complication may arise in the first step (catalytic oxidation of ammonia) that includes a side reaction reverting the nitric oxide back to nitrogen as shown below:
 $ 4N{H_3} + 6NO \to 5{N_2} + 6{H_2}O $
This side reaction can be minimised by cutting off the time in which gas mixtures come in contact with the catalyst. The overall reaction for the Ostwald process to produce nitric acid from ammonia can be written as follows:
 $ 2N{H_3}(g) + 4{O_2}(g) + {H_2}O(l) \to 3{H_2}O(g) + 2HN{O_3}(aq) $

Note:
The Ostwald process is the significant process of the modern chemical industry, as it provides the main raw materials for the production of the most common type of fertilizers. The Ostwald process is closely related with the Haber process that provides the main requisite raw material for the Ostwald process i.e. ammonia.