Q. An element $X$ crystallises in $BCC$ lattice. The edge length of unit cell is $5 A^{\circ}$ If molar mass of $X$ is $125 g m o l^{- 1},$ then calculte density of crystal.

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A

$5 g c m^{- 3}$

B

$2.66 g c m^{- 3}$

C

$1.5 g c m^{- 3}$

D

$3.33 g c m^{- 3}$

Solution:

$d = \frac{ZM}{N _{A} \times a ^{3}}$