`r_(Na^(+))" and " r_(Cl^(-))` represent radius of `Na^(+)` and `Cl^(-)` ions respectively. If 'n' is the number of NaCl units per cell then give the eqution you will use to obtain molar volume.

Explanation

Edge of the unit cell (a)=`2(r_(Na^+)+r_(Cl^-))`
Volume of the unit cell= `a^3=8(r_(Na^+)+ r_(Cl^-))^3`
Volume occupied by 1 mole of NaCl (molar volume ) =`(8(r_(Na^+)+r_(Cl^-))^3)/nxxN_0`
where `N_0` = Avogadro's number =`6.023xx10^23`