Calculate the value of Avogadro's number from the following data:
Density of `NaCl = 2.165 g cm^(-3)`
Distance between `Na^(o+)` and `Cl^(Θ)` in `NaCl = 281` pm

Explanation

For NaCl structure , a =`2(r_(Na^+)+r_(Cl^-))` or a=2 x distance between nearest neighbours ltbgt a=2 x 281 =562 pm =`562xx10^(-10)` cm
`therefore rho=(ZxxM)/(N_0xxa^3)`
`N_0=(ZxxM)/(rhoxxa^3)`
`N_0=(4xx58.5)/(58.5xx(562xx10^(-10))^3`
On calculation Avogadro's Number =`6.02xx10^23 "mol"^(-1)`