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): Graphite is soft and acts as a solid lubricant, whereas diamond is the hardest known natural substance. Reason (R): Graphite has a 2D planar structure where layers are held together by weak van der Waals forces, while diamond has a rigid 3D network of sp ³ hybridized carbon atoms. In the light of t
Options
- AAssertion (A) is false but Reason (R) is true.
- BAssertion (A) is true but Reason (R) is false.
- CBoth Assertion (A) and Reason (R) are true but Reason (R) is NOT the correct explanation of Assertion (A).
- DBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Correct answer
D. 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 correct: Graphite is soft and is used as a solid lubricant, whereas diamond is the hardest known natural substance. Reason (R) is correct and explains the Assertion: In graphite, carbon atoms are sp ² hybridized forming 2D planar hexagonal layers. These layers are held together by weak van der Waals forces, allowing them to slide over one another, which makes graphite soft and a good lubricant. In contrast, diamond has a rigid 3D network of sp ³ hybridized carbon atoms linked by strong directional