Question

Assertion: Graphite is a good conductor of electricity however diamond belongs to the category of insulators.

Reason: Graphite is soft in nature on the other hand diamond is very hard and brittle.

• A. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  
• B. Assertion and reason both are correct statements and reason is correct explanation for assertion
• C. Assertion is a correct statement but reason is a wrong statement.
  
• D. Assertion is a wrong statement but reason is correct statement.
  

Answer 1

The correct option is A Assertion and reason both are correct statements but reason is not correct explanation for assertion.


Analysing the assertion :

Graphite can conduct electricity because of the delocalised pi electrons in its structure. These arise because each carbon atom is bonded only to three other carbon atoms. However, in diamond, all the four outer electrons on each carbon atom are used in covalent bonding, so there are no delocalised electrons.​
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So, the assertion is correct.​

Analysing the reason :

Graphite has a layered structure, where the layers are held by weak van der Waals forces. This is the reason why graphite is soft in nature. In the case of diamond, it has strong covalent bonds and a compact three-dimensional structure giving it a hard and brittle structure.

So, the reason is correct but is not the correct explanation for the assertion.

Hence, both the assertion and the reason are correct statements, but the reason is not the correct explanation for the assertion.

So, option (B) is the correct answer.