A compound forms bcc unit cell with edge length $400$ pm. Determine the molar mass of the compound if the density of compound is $3.5\ \text{g cm}^{-3}$ [$N_A = 6.022 \times 10^{23}$]

What is the number of neighbouring spheres for any particle in the fcc crystal lattice ?

Identify a solution which contains solid as solute and liquid as solvent.

A solution of $50$g of solute 'X' is dissolved in $150$ g of 'Y' solvent boils at $357.27$ K. What is the molar mass of solute?
(Given $K_b$ and boiling point pure solvent is $2.77$ K kg/mol and $350.06$ K respectively.)