$1-$ Calculate the density of $CsCl$ compound using the following information:

$CsCl$ has a bcc crystal structure in which $Cs$ atoms are in the centre of unit cell and the $Cl$ atoms are in the corners, the edge length of the unit cell is $412\mathrm{.}1pm,$ Avogadro's number: $6\mathrm{.}023{10}^{23},$ Atomic weight of $Cs=133g,$ Atomic weight of $Cl=35\mathrm{.}5g.$

$2-$ By drawing a schematic image, explain why microstructural defects are good for superconducting properties.