Assertion : Graphite is an example of tetragonal crystal system.
Reason : For a tetragonal system, `a=bnec,alpha=beta=90^(@),gamma=120^(@)`.

Options

A. If both (A) and ( R) are correct and ( R) is the correct explanation of(A).
B. If both (A) and ( R) are correct, but ( R) is not the correct explanation of (A).
C. If (A) is correct, but ( R) is incorrect.
D. If both (A) and ( R) are incorrect.

Answer

D

Explanation

Graphite is an example of hexagonal crystal system (Each C-atom is `sp^(2)`- hybridized and is linked to three other C-atoms in a hexagonal planar structure). For a tetragonal system, `a=bnec,alpha=beta=gamma=90^(@)`.
For a hexagonal system `a=bnec,alpha=beta=90^(@),gamma=120^(@)`.