Question

Nitrogen exists in its elemental form as

• A. Mono atomic gas
• B. Diatomic gas
• C. Triatomic gas
• D. None of these

Answer 1

The correct option is B

Diatomic gas

Nitrogen atom is small in size and has the tendency to form $p\pi -p\pi$ multiple bonds. In fact, the Nitrogen – Nitrogen triple bond in $N_2$ molecule has very high thermodynamic stability. It has a dissociation energy 942 kj.$mo{l}^{-1}$
This makes nitrogen exist as a diatomic gas at room temperature. Also, this increased stability of the N≡N makes it non polar and hence the Van der Waals forces between the molecules are low. This is the reason why Nitrogen is a gas at room temperature. These reasons also make $N_2$ molecule pretty inert at ordinary temperatures and pressure(s).