Question

Pure ${N_2}$ can be obtained by heating ________.
A. $N{H_3}$ with $CuO$
B. $N{H_4}N{O_3}$
C. ${(N{H_4})_2}C{r_2}{O_7}$
D. $Ba{({N_3})_2}$

Answer 1

Hint: As we know that, nitrogen fixation is a process in which nitrogen in the atmosphere is converted into ammonia. Nitrogen fixation, natural and synthetic, is essential for all forms of life because nitrogen is required to biosynthesize basic building blocks of plants, animals and other life forms, e.g., nucleotides for DNA and RNA and amino acids for proteins.

Complete answer:
We know the different methods of preparation of nitrogen are:
It can be prepared from liquefaction of air and fractional distillation.
By thermal decomposition of ammonium nitrite:
$N{H_4}Cl(aq) + NaN{O_2}(aq) \to N{H_4}N{O_2}(aq) + NaCl(aq)$
Extra pure nitrogen is obtained from ammonium dichromate:
${(N{H_4})_2}C{r_2}{O_7}(aq) \to {N_2} + 4{H_2}O + C{r_2}{O_3}$
But when we talk about pure nitrogen then we know that it is obtained by barium azide which is used in the preparation of extra pure nitrogen on heating.
$Ba{({N_3})_2} \to Ba + 3{N_2}$
Therefore, pure ${N_2}$ can be obtained by heating barium azide (option D).
This nitrogen obtained in the reaction is used to make fertilizers, nitric acid, nylon, dyes and explosives. Also, the nitrogen gas can be used as an unreactive atmosphere. It is also used in this way to preserve foods and in the electronics industry during the production of transistors and diodes.
We need to remember that nitrogen makes about 78% by volume of the atmosphere. Phosphorus does not occur in free-state and is very reactive. The elements arsenic, antimony and bismuth are not very abundant.

Note:
We need to keep in mind that the top two elements, nitrogen and phosphorus, are non-metals, forming -3 charged anions. Nitrogen is a diatomic gas and phosphorus is a solid. Also, the elements like arsenic, antimony, and bismuth all have some characteristics of semi-metals such as brittleness as a free element. They have 5 electrons in their valence shell.