Answer the question on the basis of passage given below:

Nitrogen forms a large number of oxoacids such as $H_2N_2O_2$, (hyponitrous acid), $HNO_2$, (nitrous acid) and $HNO_3$, (nitric acid). Amongst these, $HNO_3$, is the most important. It is used in the manufacture of ammonium nitrate for fertilisers and other nitrates for use in explosives. It is also used to prepare many important organo-nitro compounds like nitroglycerine, trinitrotoluene etc. It acts as a strong oxidizing agent and used as an oxidiser in rocket fuels.

In the laboratory, $HNO_3$ is made by the action of sulphuric acid on nitrate salts. However, on a commercial scale, it is prepared by Ostwald's process that involves following steps:

A. Dissolution of $NO_2$ gas in water.
B. Conversion of nitric oxide to nitrogen dioxide.
C. Heterogenous catalysis in which $NH_3$ is oxidised by atmospheric oxygen.
D. Distillation of nitric acid followed by dehydration with concentrated sulphuric acid.

Arrange the above steps in the correct order.

C, B, A and D

The correct answer is Option (3) → C, B, A and D.

In Ostwald's process for the production of nitric acid, the steps can be arranged in the following order:

C. Heterogeneous catalysis in which NH₃ is oxidized by atmospheric oxygen:

The process begins with the oxidation of ammonia (\(NH_3\)) in the presence of a catalyst (typically platinum or rhodium) to form nitric oxide (\(NO\)):

\(4 \, NH_3 + 5 \, O_2 \rightarrow 4 \, NO + 6 \, H_2O\)

B. Conversion of nitric oxide to nitrogen dioxide:

The nitric oxide produced is then further oxidized in the presence of oxygen to form nitrogen dioxide (\(NO_2\)):

\(2 \, NO + O_2 \rightarrow 2 \, NO_2\)

A. Dissolution of NO₂ gas in water:

The nitrogen dioxide is then dissolved in water, where it reacts to form nitric acid and nitric oxide:

\( 3 \, NO_2 + H_2O \rightarrow 2 \, HNO_3 + NO\)

D. Distillation of nitric acid followed by dehydration with concentrated sulfuric acid:

Finally, the nitric acid solution may be concentrated by distillation, and further dehydration can be achieved using concentrated sulfuric acid if needed.

Thus, the correct sequence of steps is: C, B, A, and D.