# Iron crystallizes in a bcc system with a lattice parameter of $2.861A^{\large\circ}$.Calculate the density of iron in the bcc system.(Given : Atomic weight of $Fe=56,N=6.023\times 10^{23}mol^{-1}$)

$\begin{array}{1 1}6.5gcm^{-3}\\7.5gcm^{-3}\\8.5gcm^{-3}\\4.5gcm^{-3}\end{array}$

Density,$\rho=\large\frac{zM}{Na^3}$ for bcc,$z=2$
$\rho_{Fe}=\large\frac{2\times 56.0}{6.023\times 10^{23}\times 2.861\times 10^{-8}}$
$\quad\;\;=6.5gcm^{-3}$