`CsBr` crystallises in a body`-` centred cubic lattice. The unit cell length is `436.66 p m`. Given that `:` the atomic mass of `Cs=133` and that of `Br=80 gram` and Avogadro's number being `6.02xx10^(23)mol^(-1)`, the density of `CsBr` is `:`

Options

A. `42.5 g/cm^(3)`
B. ` 0.425 g/cm^(3) `
C. `8.25 g/cm^(3)`
D. ` 4.25 g/cm^(3) `

Answer

D

Explanation

For CsBr no. of formulas/unit cell
n=1(like CsCI type)
`C.D=(nxxM)/(VxxN_(A))``[{:(M=133+80=213),(V=a^(3)=(436.6xx10^(-12))^(3)):}]`
`C.D=(1xx213gm)/(83.22xx10^(-12)cm^(3)xx6.02xx10^(23))=4.25gm//cm^(3)`