Assertion (A) : In sodium chloride crystal, `Na^(o+)` ions occupy `OVs` while `Cl^(ɵ)` ions occupy vertices of octahedron.
Reason (R ) : The radius ratio of `Na^(o+) : Cl^(ɵ)` lies between `0.4` and `0.7`.

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)` is incorrect, but `(R)` is correct.

Answer

D

Explanation

Correct (A): `Na^(o+)` ions occupy all `OVs` but `Cl^(ɵ)` ions occupy lattice points `("corner" + "face centres")`.
(R) is correct, for `OV, r_(o+) + r_(ɵ) = 0.414 - 0.732`