Question

Assertion :Dinitrogen is chemically unreactive at ordinary temperature and is very stable. Reason: The bond dissociation energy is $946kJmo{l}^{-1}.$

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Nitrogen is chemically unreactive at room temperature due to high bond enthalpy of N≡N bond but becomes reactive at elevated temperatures (on heating or in the presence of catalysts).

The triple bond is pretty strong. Therefore, it needs a lot of energy to break those bonds and participate in a reaction. So, nitrogen is commonly referred to used as an inert gas (high abundance & low cost).

Dissociation energy of its molecule is fairly high.

Larger the bond dissociation enthalpy, stronger will be the bond in the molecule. So, $N_2$ molecule has bond dissocaition energy = $946kJmo{l}^{-1}$.

Hence , Both Assertion and Reason are correct and Reason is the correct explanation for Assertion .

Hence , option A is correct .