What is the density of `Na_(2)O` having antifluorite-type crystgal stryctutre, if the edge length of cube is `100 gm` and what is the effect on density by `0.05%` Frenkel defect?

Options

A. ` 823. 5 g m^(-3)`, density decreases
B. ` 414. 16 g cm^(-3)` density decareases
C. ` 823.5 g cm^(-3)` , densityn remanins same
D. ` 141.16 g cm^(-3)`, density remanins same

Answer

D

Explanation

Density `(rho) = (Z_(eff) xx M_w)/((N)A xx A^(3))`
(For antifluorite, ` Z_(eff) =4//"unit cell")`
` rho = (4xx[23 xx 2+ 16])/( 6 xx 10^(23) xx (100 p mxx 10^(-10) cm^3))`
` [(1 p m = 10^(12) m),(=10^(10) cm)] = 414 . 16 g cm^(-3)`.