A compound forms hexagonal closed packed structure. What is the number of tetrahedral voids in 0.8 mol of it?

\(9.635 × 10^{23}\)

The correct answer is option 3. \(9.635 × 10^{23}\).

Number of atoms in close packaging = 0.8 mol

\(1 mol\) has \(6.022 × 10^{23}\) particles

So, the number of close-packed particles \(= 0. 8 × 6.022 × 10^{23} = 4.817 × 10^{23}\)

Number of tetrahedral voids = 2 × number of atoms in close packaging

Plug the values we get

Number of tetrahedral voids \(2 × 4.817 × 10^{23} = 9.6352 × 10^{23}\)