In NaCl the nearest neighbour distance of ions is 
a) a/4
b) a(3)1/2/2
c) a/2
d) a(2)1/2​/2

Dear Student,

NaCl has a face centered cubic(fcc) structure.

Each Na⁺ ion has 6 Cl^- ions as neighbours and each Cl^- ion has 6 Na⁺ ions as neighbours.
Thus, the coordination number of NaCl is 6.

The nearest neighbout distance is $\frac{a}{2}$.

The correct answer is option (c).

Hope it helps.

Regards