Question

1. Name the process by which nitric acid is obtained on a large scale.
2. Name the reactant used.
3. (i) Name the catalyst used. (ii) Upto what temperature is the catalyst heated. (iii) Give the reaction taking place in the catalytic chamber. (iv) Name the products formed.

Answer 1

1. The process by which nitric acid is obtained on a large scale is Ostwald's process.
2. The reactant used in Ostwald's process are Ammonia, oxygen of air. A mixture of air and dry ammonia in the ratio of 10:1 by volume is used.

1. The catalyst used in Ostwald's process is platinum with 10 % rhodium.
2. In Ostwald's process the ammonia and metal catalyst is heated to a temperature around 600-800 degrees Celsius.
3. In the Catalytic oxidation chamber it uses catalysts like platinum gauze or copper and nickel is used and the oxidation of ammonia takes place and is converted into nitric oxide and the process is reversible and exothermic.

$$\begin{gathered} \underset{\mathrm{ammonia}}{\underset{}{4{\mathrm{NH}}_3\left(\mathrm{g}\right)}}+\underset{\mathrm{oxygen}}{\underset{}{5{\mathrm{O}}_2\left(\mathrm{g}\right)}}\to \underset{\mathrm{nitrogen}\mathrm{oxide}}{\underset{}{4\mathrm{NO}}\left(\mathrm{g}\right)}+6{\mathrm{H}}_2\mathrm{O}+\mathrm{heat} \\ \underset{\mathrm{nitrogen}\mathrm{oxide}}{\underset{}{2\mathrm{NO}\left(\mathrm{g}\right)}}+\underset{\mathrm{oxygen}}{\underset{}{{\mathrm{O}}_2\left(\mathrm{g}\right)}}\to \underset{\mathrm{nitrogen}\mathrm{dioxide}}{\underset{}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)}} \\ \underset{\mathrm{nitrogen}\mathrm{dioxide}}{\underset{}{3{\mathrm{NO}}_2\left(\mathrm{g}\right)}}+\underset{\mathrm{water}}{\underset{}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}}\to \underset{\mathrm{nitric}\mathrm{acid}}{\underset{}{2{\mathrm{HNO}}_3\left(\mathrm{aq}\right)+\mathrm{NO}\left(\mathrm{g}\right)}} \end{gathered}$$

iv. The product formed in Ostwald's process is Nitric acid and Nitrogen oxide.