Question

State physical and chemical properties of nitrogen is ………………..

Answer 1

Hint: An element or substance is characterised by physical and chemical properties. Physical properties are related with the appearance and chemical properties define its nature and interaction.

Complete answer:
Physical and chemical properties of nitrogen:
> Nitrogen element belongs to Group15. It differs from the rest of the members of Group15 due to its small size, high electronegativity, high ionisation enthalpy and absence of vacant d – orbitals.
> Nitrogen exists as a diatomic molecule with a triple bond. Thus, its bond enthalpy is very high. Catenation tendency is weaker in nitrogen as single $N-N$ bond is weaker than single $P-P$ bond, as high inter electronic repulsion of non – bonding electrons, owing to small bond length in nitrogen. Nitrogen has the unique ability to form ${p_\pi } - {p_\pi }$ multiple bonds with itself. Nitrogen shows maximum covalency of four because of absence of vacant d – orbitals.
Thus, nitrogen cannot form ${d_\pi } - {d_\pi }$ bond.
> It is a colourless, odourless, tasteless and non – toxic gas. It has two stable isotopes ${N^{14}}$ and ${N^{15}}$. It has very low solubility in water and low freezing and boiling point. Dinitrogen is inert at room temperature because high bond enthalpy of $N \equiv N$ bond increases with increase in temperature reactivity increases.
> It directly combines with some metals to form ionic nitrides.

$6Li + {N_2}\xrightarrow{{}}2L{i_3}N$
$3Mg + {N_2}\xrightarrow{{}}M{g_3}{N_2}$

> It combines with ${H_2}$ at about $773K$ in the presence of catalyst to form ammonia

At high temperature $\left( { \approx 200K} \right)$

${N_2}\left( g \right) + {O_2}\left( g \right)\overset \Delta \leftrightarrows 2NO\left( g \right)$

Note: Nitrogen $\left( {{N_2}} \right)$ is used in the manufacture of ammonia and other industrial chemicals containing ${N_2}$ (For example: Calcium cyanamide). Nitrogen is used to create an inert atmosphere (For example: In the iron and steel industry). Liquid ${N_2}$ is used as a refrigerant to preserve biological material, food items and in cryosurgery.