AP EAMCET Engineering 22 Apr 2019 Shift 1 Paper

The number of atoms is calculated as:
For 0.5‌mol=0.5×6.022×1023
=3.011 ×1023
Tetrahedral voids is equal to 2 × Number of atoms of metal
Octahedral voids is equal to number of atoms of metal
Therefore,
Number of tetrahedral voids =2 ×3.011×1023
=6×1023
=1‌mol
Number of octahedral voids =3.011×1023
=0.5‌mol
The total number of voids is 1+0.5=0.5‌mol