Find the volume occupied by a particle in a simple cubic unit cell if the radius of a particle in it is 190 pm.

Calculate the number of unit cells in $1\text{cm}^3$ of metal if it forms simple cubic structure with unit cell edge length 500 pm.

Which of the following concentrations of solutions of urea in water exhibits minimum freezing point depression?

Calculate van't Hoff factor for aqueous solution of 0.02 m formic acid if it freezes at -0.045 $^\circ\text{C}$.
[ $K_f$ = 1.86 K kg $\text{mol}^{-1}$ and freezing point of water = $0\ ^\circ\text{C}$ ]