Question

CsBr crystallizes in a body-centred cubic lattice of unit cell edge length $436.6$ pm. Atomic masses of Cs and Br are $133$ amu and $80$ amu respectively. The density (in g cm${}^{-3}$) of CsBr is :

• A. $8.50$
• B. $4.25$
• C. $42.5$
• D. $0.425$

Answer 1

The correct option is A $8.50$

For bcc, z=4

The formula for density is given below:

$\text{Density}=\frac{z\times M}{a^3\times N_0}$

$=\frac{2\times 213}{(4.366\times {10}^{-8}{)}^3\times 6.02\times {10}^{23}}$

$=8.50$ g cm${}^{-3}$

Hence, the correct option is $\text{A}$