Question

In one of the following reactions $ \text{HN}{{\text{O}}_{\text{3}}} $ does not behave as an oxidizing agent. Identify it:

• A. $ {{I}_{2}}+10HN{{O}_{3}}\xrightarrow{{}}2HI{{O}_{3}}+10N{{O}_{2}}+4{{H}_{2}}O $
• B. $ 3Cu+8HN{{O}_{3}}\xrightarrow{{}}3Cu{{(N{{O}_{3}})}_{2}} $ $ +\,2NO+4{{H}_{2}}O $
• C. $ 4Zn+10HN{{O}_{3}}\xrightarrow{{}}4Zn{{(N{{O}_{3}})}_{2}} $ $ +\,N{{H}_{4}}N{{O}_{3}}+3{{H}_{2}}O $
• D. $ 2HN{{O}_{3}}+{{P}_{2}}{{O}_{5}}\xrightarrow{{}}2HP{{O}_{3}}+{{N}_{2}}{{O}_{5}} $

Answer 1

The Correct Option is D

[a] $ {{\text{I}}_{\text{2}}}\text{+}\,\text{10}\overset{\text{+}\,\text{5}}{\mathop{\text{HN}}}\,{{\text{O}}_{\text{3}}}\xrightarrow{{}} $
$ 2HI{{O}_{3}}+10\overset{+2}{\mathop{NO}}\,\,+\,4{{H}_{2}}O $
In the reaction $ \text{HN}{{\text{O}}_{\text{3}}} $
is acting as oxidizing agent because i|Ls oxidation state is decreasing from + 5 to + 2.
[b] $ \text{3Cu}\,\text{+}\,\text{8}\overset{\text{+5}}{\mathop{\text{HN}}}\,{{\text{O}}_{\text{3}}}\xrightarrow{{}} $
$ 3Cu{{(N{{O}_{3}})}_{2}}+2\overset{+2}{\mathop{NO}}\,+4{{H}_{2}}O $
It is reaction in which $ \text{HN}{{\text{O}}_{\text{3}}}
$ is acting as oxidising agent because oxidation number of nitrogen is decreasing.
[c] $ 4Zn+10\overset{+5}{\mathop{HN}}\,{{O}_{3}}\xrightarrow{{}}4Zn{{(N{{O}_{3}})}_{2}} $
$ +\,N{{H}_{4}}\,{{\overset{+2}{\mathop{NO}}\,}_{3}}\,+3{{H}_{2}}O $
$ \therefore $ It is also a reaction, in which $ \text{HN}{{\text{O}}_{\text{3}}} $ is oxidizing agent.
[d] $ 2HN{{O}_{3}}+{{P}_{2}}{{O}_{5}}\xrightarrow[{}]{{}}2HP{{O}_{3}}+{{N}_{2}}{{O}_{5}} $
$ {{P}_{2}}{{O}_{5}} $ dehydrating agent.
So in this reaction $ \text{HN}{{\text{O}}_{\text{3}}} $ does not act as oxidizing agent.