The density of `KBr` is `2.75 g cm^(-3)`. The length of the unit cell is `654` pm. Atomic mass of `K = 39, Br = 80`. Then what is true about the predicted nature of the solid?

Options

A. Face centred cubic
B. simple cubic system
C. body centred cubic system
D. none of these

Answer

A

Explanation

`Z=(d xxa^(3)xxN_(0)xx10^(-30))/(M)" "(becausea=cm)`
`=(2.85xx(654)^(3)xx(6.02xx10^(23))xx10^(-30))/(39+80)=3.9~~4`
Hence, it is face-centred.