Question

Select the correct statement(s):
A.Ostwald’s method of preparation of $NH{O_3}$ is based upon catalytic oxidation of $N{H_3}$ by atmospheric oxygen.
B.$HN{O_2}$ can act as both oxidising and reducing agents.
C.$N{O_2}$ reacts with ${O_3}$ to form ${N_2}{O_5}$ .
D.$HN{O_3}$ can be used as both oxidising and reducing agent.

Answer 1

Here, we have been given four statements, and we are asked to find out the correct statement(s). We must know the preparation and nature of $HN{O_3}$ , nature of $HN{O_2}$ and the reaction of $N{O_2}$ with ozone. Also, a knowledge about Ostwald’s process would prove to be helpful to solve the question.

Complete step by step solution:
Ostwald’s process is a commonly used method to synthesise nitric acid ( $HN{O_3}$ ) using ammonia ( $N{H_3}$ ) in the presence of a catalyst such as platinum-rhodium ( $Pt/Rh$ ) or vanadium pentoxide ( ${V_2}{O_5}$ ). The basic principle behind this process is oxidation.
In nitrous acid ( $HN{O_2}$ ), the oxidation state of $N$ is $+ 3$. Hence it can further be oxidised as well as reduced to form compounds with different oxidation states. The oxidation state of $N$ varies from $- 3$ to $+ 5$ . Therefore, nitrous acid can potentially act as both oxidising and reducing agents.
Nitrogen dioxide ( $N{O_2}$ ) reacts with ozone ( ${O_3}$ ) in the following way:
$2N{O_2}{\text{ (g)}} + {O_3}{\text{ (g)}} \to {N_2}{O_5}{\text{ (g)}} + {O_2}{\text{ (g)}}$
Therefore, the reaction of nitrogen dioxide with ozone leads to the formation of dinitrogen pentoxide, which is commonly known as nitrogen pentoxide or nitric anhydride.
The oxidation state of nitrogen in nitric acid ( $HN{O_3}$ ) is +5, which is the highest oxidation state in which nitrogen can exist. Therefore, nitric acid is a powerful oxidising agent, meaning that it can get itself reduced while oxidising another substance or species.

Hence, options (A), (B), and (C) are the correct answers.

Note:
Remember that the question is to find out the correct statements from the given set of statements. Improper reading of the question may lead the students to mark the answers wrong, as the question also intentionally requires the readers to have a clear idea of the concepts.