Iron crystallises in a bcc system with a lattice parameter of 2.861 Å. Calculate the density of iron in the bcc system. (atomic weight of `Fe = 56, N_A = 6.023 xx 10^(23) mol^(-1)` )

Options

A. `7.94 g mL^(-1)`
B. `8.96 g mL^(-1)`
C. `2.78 g mL^(-1)`
D. `6.72 g mL^(-1)`

Answer

A

Explanation

`rho = (ZxxM)/(N_A xxa^3)`
For bcc, Z=2
`rho_(Fe) =(2 xx 56.0)/(0.023xx10^(23) xx (2.861x10^(-8))^3) = 7.94 g mL^(-1)`