Question

The Ostwald process is used to produce:

• A. Nitric acid
• B. Sulfuric acid
• C. Hydrochloric acid
• D. Phosphoric acid

Hint:

Remember: Ostwald process = Nitric acid, Contact process = Sulfuric acid. These are commonly paired in exam questions.

Answer 1

The Correct Option is A

The Ostwald process is an industrial method used for the large-scale production of nitric acid (HNO$_3$) from ammonia (NH$_3$). It was developed by Wilhelm Ostwald in the early 20th century.
The process involves the following key steps:
1. Oxidation of ammonia:
\[ 4NH_3 + 5O_2 \rightarrow 4NO + 6H_2O (\text{in presence of Pt-Rh catalyst at 800°C}) \]
2. Oxidation of nitric oxide:
\[ 2NO + O_2 \rightarrow 2NO_2 \]
3. Absorption of NO$_2$ in water:
\[ 3NO_2 + H_2O \rightarrow 2HNO_3 + NO \]
The nitric oxide (NO) released in the last step is recycled back into the process.
This method is essential for manufacturing fertilizers like ammonium nitrate and for other nitration reactions in chemical industries.
Other acids mentioned in the options are produced by different processes:
- Sulfuric acid — Contact process
- Hydrochloric acid — Direct synthesis of H$_2$ and Cl$_2$
- Phosphoric acid — Wet process using phosphate rock and sulfuric acid
Thus, the Ostwald process specifically refers to the production of nitric acid.