Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Both rhombic and monoclinic sulphur exist as S$_8$ while oxygen exists as O$_2$.
{Reason (R): Oxygen forms $p\pi$-$p\pi$ multiple bonds with itself and other elements having small size and high electronegativity like C, N, which is not possible for sulphur.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Answer 1

The Correct Option is C

This question concerns the allotropes of sulfur and oxygen and their bonding characteristics. The provided Assertion (A) and Reason (R) are analyzed as follows:

1. Assertion (A): Rhombic and monoclinic sulfur exist as S₈, whereas oxygen exists as O₂.
   • Sulfur's capacity to form single bonds with itself enables the creation of extended chains and rings. Both rhombic and monoclinic sulfur primarily exist in the stable S₈ ring allotrope.
   • Oxygen, in contrast, characteristically forms a double bond with itself, yielding the diatomic O₂ molecule.
   • Therefore, Assertion (A) is accurate.
2. Reason (R): Oxygen forms $p\pi$-$p\pi$ multiple bonds with itself and with other small, highly electronegative elements like C and N, a capability sulfur lacks.
   • Oxygen's small size and high electronegativity facilitate the formation of strong $p\pi$-$p\pi$ bonds through effective lateral overlap of p orbitals, an interaction not feasible for the larger, less electronegative sulfur.
   • While this statement accurately describes oxygen's bonding, it does not explain sulfur's existence as S₈. The formation of S₈ rings in sulfur is primarily a consequence of its valence electron configuration enabling single bond formation, rather than a deficiency in its ability to form $p\pi$-$p\pi$ bonds.
   • Consequently, Reason (R) does not correctly explain why sulfur exists as S₈.
3. Conclusion: Given that Assertion (A) is correct and Reason (R) is not the correct explanation, the most appropriate response is:

(A) is correct but (R) is not correct.