Ammonium chloride crystallizes in a body-centered cubic $(BCC)$ lattice with a unit cell edge length of $390 \ pm$. If the radius of the chloride ion is $180 \ pm$, what is the radius of the ammonium ion in $pm$?

The second order Bragg's diffraction of $X$-rays with $\lambda = 1 \ \mathring{A}$ from a set of parallel planes in a metal occurs at an angle of $60^\circ$. The distance between the scattering planes in the crystal is ................ $\mathring{A}$.

$A$ metal has a $fcc$ lattice. The edge length of the unit cell is $404 \, pm$. The density of the metal is $2.72 \, g \, cm^{-3}$. The molar mass of the metal is :- ............ $g \, mol^{-1}$ ( $N_A$ Avogadro constant $= 6.02 \times 10^{23} \, mol^{-1}$ )

Calculate the density of a metal which forms a simple cubic structure with an edge length of unit cell $336 \ pm$. ($90 \ g$ of metal contains $2.64 \times 10^{23}$ atoms) (in $g \ cm^{-3}$)

Calculate the volume of the unit cell when a metal having a density of $1 \ g \ cm^{-3}$ and a molar mass of $23 \ g \ mol^{-1}$ crystallizes to form a $bcc$ structure.

For a simple cubic system,find the ratio of the interplanar distances between the $(100)$,$(110)$,and $(111)$ planes.