Question

The nitrogen containing compound produced in the reaction of $HN{{O}_{3}}$ with ${{P}_{4}}{{H}_{10}}$ is:
A) Can also be prepared by reaction of ${{P}_{4}}$ and $HN{{O}_{3}}$
B) Is diamagnetic
C) Contains one N-N bond
D) Reacts with Na metal producing a brown gas

Answer 1

The nitric acid is referred to as aqua fortis which is corrosive mineral acid. The pure compounds of it are colourless but the old samples due to decomposition are yellow in colour. It has a white crystalline solid. It is widely used as a drying or dehydrating agent.

Complete step by step answer:
nitric acid is also known as the spirit of niter. Whereas the phosphorus pentoxide which is crystalline white colour solid and is considered as the anhydride of phosphoric acid. It has the tendency to desiccant or dehydrate the compound so it is a strong dehydrating agent. When the nitric acid is reacted with phosphorus pentoxide it gives the anhydride of nitric acid and acid of phosphorus. So the reaction of them is the following:
$4HN{{O}_{3}}+{{P}_{4}}{{H}_{10}}\to 2{{N}_{2}}{{O}_{5}}+4HP{{O}_{3}}$
So the nitrogen containing compound formed is ${{N}_{2}}{{O}_{5}}$.
So according to the option ‘a’ if we react ${{P}_{4}}$ with $HN{{O}_{3}}$ the compounds formed are phosphoric acid, nitrogen dioxide and water. the reaction for it is given below:
${{P}_{4}}+20HN{{O}_{3}}\to 4{{H}_{3}}P{{O}_{4}}+20N{{O}_{2}}+4{{H}_{2}}O$
The formation of ${{N}_{2}}{{O}_{5}}$does not take place. So option a is incorrect.
The presence of the unpaired electrons leads to paramagnetism and when the electrons are completely paired they are diamagnetic. The dinitrogen pentoxide is diamagnetic in nature because it has an even number of electrons and all the electrons are fully paired in it. So the option b is correct.
The structure of dinitrogen pentoxide does not contain the N-N bond; the nitrogen is bonded to oxygen present between them.
So according to option d if we react the dinitrogen pentoxide with sodium the nitrogen gas is evolved which is brown in colour. The reaction is the following:
${{N}_{2}}{{O}_{5}}+Na\to NaN{{O}_{3}}+N{{O}_{2}}$
So option d is correct.
So the correct options for this question are option ‘b’ and option ‘d’.

Note: if the inhalation of nitric acid is done then it can be irritant and burns the lungs throat severely. It can even cause pulmonary edema and death. It is used as an oxidizer in liquid fueled rockets and in the manufacturing of TNT. It is used in electrochemistry as a doping agent.