Assertion (A) : Graphite is an example of tetragonal crystal system.
Reason (R ) : For a tetragonal system, `a = b != c` and `alpha = beta = 90^(@), gamma = 120^(@)`.

Options

A. if both Assertion and Reason are true and reason is the correct explanation of the assertion.
B. if both assertion and reason are true but reason is not the correct expalanation of the assertion
C. if assertion is true, reason is false
D. both assertion and reason are false statements.

Answer

d

Explanation

Graphite has a two dimensional sheet structure. Each C-atom is in `sp^(2)` hybridised state and is linked to three other carbon atoms in a hexagonal planar structure.
For a tetragonal system `a=b ne, c alpha= beta=90^(@)`
For a hexagonal system `a=b=ne,c alpha= beta, =90^(@)`
`gamma=120^(@)`