Industrial Chemistry

Ostwald’s Process for Nitric Acid Manufacture:
The Ostwald process is the commercial method for producing nitric acid. It involves the catalytic oxidation of ammonia in three main steps: 1. Oxidation of ammonia to nitric oxide: 2. Oxidation of nitric oxide to nitrogen dioxide: 3. Absorption of nitrogen dioxide in water to form nitric acid: Thus, nitric acid is obtained industrially using the Ostwald process. (i) Reaction of Zinc metal with conc. HNO :
Concentrated nitric acid is an oxidizing acid. With zinc, it forms zinc nitrate and nitrogen dioxide.
(ii) Reaction of Iodine with conc. HNO :
Concentrated nitric acid oxidizes iodine to iodic acid.
Conclusion:
- The Ostwald process is the standard industrial route for nitric acid manufacture.
- Conc. HNO acts as a strong oxidizing agent, oxidizing both zinc and iodine to their higher oxidation states while releasing NO .

Step 1: Type of reaction.
When sodium nitrate is heated with concentrated sulphuric acid, nitric acid vapours are liberated.
Step 2: Balanced reaction.
Step 3: Conclusion.
This is the laboratory method of preparing nitric acid.

Step 1: Ostwald’s process.
Ostwald’s process is used for large-scale manufacture of nitric acid from ammonia. Step 2: Reactions involved.
Step 3: Detection of nitrate ion (NO ).
Brown ring test is used. The solution containing nitrate is treated with freshly prepared FeSO solution and concentrated H SO is added along the sides of the test tube. A brown ring appears at the junction, indicating the presence of NO . Reaction: Conclusion:
Ostwald’s process produces nitric acid from ammonia using catalytic oxidation. The presence of nitrate ions can be confirmed by the brown ring test.