$NH_4Cl$ crystallizes in a $bcc$ lattice. If the edge length of the unit cell is $387 \, pm$, the distance between oppositely charged ions is ........ $pm$.

$A$ metal crystallises in $bcc$ lattice with unit cell edge length of $300 \ pm$ and density $6.15 \ g \ cm^{-3}$. The molar mass of the metal is

Derive the expression to calculate the density of a unit cell.

For a crystal,the first-order Bragg reflection of $X$-rays with a wavelength of $2.29 \times 10^{-10} \ m$ occurs at an angle of $27^\circ 8'$. Calculate the distance between two parallel planes.

Calculate the number of atoms per unit cell of an element having a molar mass of $92.0 \ g \ mol^{-1}$ and a density of $8.6 \ g \ cm^{-3}$ forming a cubic unit cell structure. Given $[a^3 \times N_{A} = 21.5 \ cm^3 \ mol^{-1}]$.

Aluminium metal has a density of $2.72 \ g \ cm^{-3}$ and crystallizes in a cubic lattice with an edge length of $404 \ pm$. Which of the following is correct?