Answer the question on the basis of the passage given below:
Molecular nitrogen is very little reactive chemically. During lightning discharge, atmospheric nitrogen and oxygen combine to form nitric oxide which also combines with oxygen to form nitrogen dioxide. Both \(NO\) and \(NO_2\) constitute smog which is very poisonous. It can cause a burning sensation in the eyes and adversely affect the respiratory system.
Molecular nitrogen is very little reactive since it has:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → high bond order
Nitrogen is small and forms strong pπ–pπ bonds, so the two atoms of \( \ce{N2} \) are joined by a triple bond (one σ and two π bonds). The molecular orbital configuration of \( \ce{N2} \) (14 electrons) gives the same result:
\( \sigma1s^2\,\sigma^*1s^2\,\sigma2s^2\,\sigma^*2s^2\,(\pi2p_x^2 = \pi2p_y^2)\,\sigma2p_z^2 \)
\( \displaystyle \text{Bond order} = \frac{N_b - N_a}{2} = \frac{10 - 4}{2} = 3 \)
A bond order of 3 means a very short and very strong bond: the bond enthalpy of N≡N is 941.4 kJ mol−1. A large amount of energy is needed to break it, so dinitrogen is almost inert at room temperature and reacts only at high temperature.
Why the other options are incorrect
Option (2) electrostatic force of attraction — Incorrect. \( \ce{N2} \) is a non-polar covalent molecule made of two identical atoms; there are no ions and no electrostatic attraction in it.
Option (3) \(sp^3\) hybridization — Incorrect. Each nitrogen in \( \ce{N2} \) is sp hybridised (linear, triple bond). sp3 nitrogen is found in \( \ce{NH3} \), which is a reactive molecule.
Option (4) \(d^2sp^3\) hybridization — Incorrect. Nitrogen is a second-period element and has no d orbitals; d2sp3 hybridisation belongs to the metal ion of inner-orbital octahedral complexes such as \( \ce{[Co(NH3)6]^{3+}} \).
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Properties – “… Dinitrogen is rather inert at room temperature because of the high bond enthalpy of N≡N bond. Reactivity, however, increases rapidly with rise in temperature.”