A compound forms hcp structure. What is the total number of voids in 0.5 mol of it ? How many of these are tetrahedral voids ?

Explanation

The Total no. of voids = The no. of octahedral voids + the no. of tetrahedral voids present in the compound.
Given : no of moles = 0.5 mol
`because` 1 mol contains `6.022 xx 10^(23)` atoms
`therefore` 0.5 mol contains `6.022 xx 10^(23) xx 0.5`
`= 3.011 xx 10^(23)` atoms
`because` No. of octahedral voids present in the
Compound `= 3.011 xx 10^(23)` voids
`therefore` No. of tetrahedral voids
`= 2 xx` no. of octahedral voids
`= 2 xx 3.011 xx 10^(23)`
`= 6.022 xx 10^(23)`
`therefore` Total no. of voids
`= 3.011 xx 10^(23) + 6.022 xx 10^(23)`
`= 9.033 xx 10^(23)` voids