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Assertion: Hexagonal close packing in mo...

Assertion: Hexagonal close packing in more light than cubic close packing.
Reason: Hexagonal close packing has C.N of 12 whereas cubic close packing has C.N. of 8.

A

If both assertion and reason are correct and reason is correct explanation for assertion

B

If both assertion and reason are correct but reason is not correct explanation for assertion

C

If assertion is correct but reason is incorrect

D

If both assertion and reason are incorrect

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both the assertion and the reason provided regarding hexagonal close packing (HCP) and cubic close packing (CCP). ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "Hexagonal close packing is more tightly packed than cubic close packing." - To evaluate this, we need to consider the packing efficiency of both structures. 2. **Packing Efficiency**: - Both hexagonal close packing (HCP) and cubic close packing (CCP) have a packing efficiency of 74%. This means that they occupy the same volume fraction in a given space. - Therefore, the assertion that HCP is more tightly packed than CCP is **false**. 3. **Understanding the Reason**: - The reason states that "Hexagonal close packing has a coordination number (C.N.) of 12 whereas cubic close packing has a coordination number of 8." - Coordination number refers to the number of nearest neighbors surrounding a particle in a crystal structure. 4. **Coordination Numbers**: - In both hexagonal close packing and cubic close packing, the coordination number is actually 12. - In HCP, each sphere is surrounded by 6 spheres in the same layer, and 3 spheres in the layer above and 3 in the layer below, totaling 12. - Similarly, in CCP, the arrangement is such that each sphere also has 12 nearest neighbors. - Therefore, the reason provided is also **false**. 5. **Conclusion**: - Since both the assertion and the reason are false, the correct answer is that both statements are incorrect. ### Final Answer: Both the assertion and the reason are incorrect.
To solve the question, we need to analyze both the assertion and the reason provided regarding hexagonal close packing (HCP) and cubic close packing (CCP). ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "Hexagonal close packing is more tightly packed than cubic close packing." - To evaluate this, we need to consider the packing efficiency of both structures. ...
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