Question

The Ostwald process for the commercial production of nitric acid from ammonia and oxygen involves the following steps:

4NH3(g)+5O2(g)------->4NO(g)+6H2O(g) -908 kj/mol (delta H)

2NO(g)+O2(g)----------->2NO2(g) -112 kj/mol

3NO2(g)+H2O(l)-------->2HNO3(aq)+NO(g) -140 kj/mol

Write the overall equation for the production of nitric acid by the Ostwald process by combining the preceding equations (Water is also a product).

Answer 1

The Ostwald process involves three reactions to produce nitric acid from ammonia and oxygen. By combining and canceling out common species in the given reactions, we derive the balanced overall chemical equation for the Ostwald process, which is 4NH3(g) + 7O2(g) → 4NO2(g) + 2H2O(l) + 4HNO3(aq).

Step-by-step explanation:

The Ostwald process is used for the commercial production of nitric acid (HNO3) from ammonia and oxygen. To write the overall equation for this process, we combine the three given reactions:

Combining these equations while canceling out common species on both sides:

4NH3(g) + 5O2(g) + 2NO(g) + O2(g) + H2O(l) → 4NO(g) + 6H2O(g) + 2NO2(g) + NO(g) + 2HNO3(aq)

After canceling, we get the overall equation:

4NH3(g) + 5O2(g) → 4NO2(g) + 6H2O(g) + 2HNO3(aq)

However, this is not balanced in terms of nitrogen species. We need to consider that for every two molecules of NO2 that form nitric acid, one molecule of NO is regenerated and recycled into the process. Consequently, the correct balanced overall equation will be:

4NH3(g) + 7O2(g) → 4NO2(g) + 2H2O(l) + 4HNO3(aq)