In each of the following question, a statement of Assertion (A) is given followed by a corresponding statement of Reason (R). Choose the correct answer as:

Assertion (A): Nitrogen is less reactive than molecular oxygen.

Reason (R):  The bond length of N₂ is shorter than that of oxygen.

If both assertion and reason are true, but the reason is not the correct explanation of the assertion.

The correct answer is option 2. If both assertion and reason are true, but the reason is not the correct explanation of the assertion.

Let is break down the assertion and reason provided:

Assertion (A) - Nitrogen is less reactive than molecular oxygen

This assertion is true. Nitrogen gas \((N_2)\) is less reactive than molecular oxygen \((O_2)\) under normal conditions. Nitrogen gas is relatively inert and does not readily react with other substances at room temperature and atmospheric pressure. In contrast, oxygen gas is more reactive and readily participates in various chemical reactions, such as combustion, oxidation, and supporting respiration.

Reason (R) - The bond length of \(N_2\) is shorter than that of oxygen

This reason is also true. The bond length of N2 (nitrogen gas) is indeed shorter than that of \(O_2\) (oxygen gas). In \(N_2\), the nitrogen atoms are held together by a triple bond, which is shorter and stronger than the double bond between oxygen atoms in \(O_2\). The shorter bond length of \(N_2\) indicates a stronger bond between the nitrogen atoms.

However, the reason provided does not offer a direct explanation for why nitrogen is less reactive than oxygen. While it's true that \(N_2\) has a shorter bond length, it doesn't inherently imply lower reactivity. The differences in reactivity between nitrogen and oxygen stem from factors such as electronegativity, bond strength, and the tendency to form stable compounds.

In summary, both the assertion and reason are true, but the reason provided does not adequately explain why nitrogen is less reactive than oxygen. Nitrogen's lower reactivity is influenced by factors beyond bond length, such as electronegativity and stability of compounds formed. Therefore, option 2 is the correct choice.