NEETChemistryp Block Elements (Group 15, 16, 17 & 18)
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Phosphorus shows a much greater tendency for catenation than nitrogen. Reason (R): The N - N single bond is weaker than the P - P single bond due to high interelectronic repulsion among non-bonding electrons. In the light of the above statements, choose the most appropriate answer from the options
Options
- ABoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- BBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- CAssertion (A) is true but Reason (R) is false.
- DAssertion (A) is false but Reason (R) is true.
Correct answer
B. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Step-by-step solution
Assertion (A) is true: Phosphorus has a strong tendency for catenation (forming P ₄ molecules and polymeric chains), whereas nitrogen has a very limited tendency for catenation. Reason (R) is true: The N - N single bond is weaker than the P - P single bond. This is because the small size of the nitrogen atom leads to high interelectronic repulsion between the non-bonding (lone pair) electrons on the adjacent atoms. The extent of catenation depends directly on the strength of the element-element single bond. Since t