$Ag$ crystallises in $fcc$ lattice. What is the total number of tetrahedral voids present in $540 \ g$ of $Ag$ metal (in $N_A$)? $(N_A = \text{Avogadro number}; Ag \text{ atomic weight} = 108 \ g \ mol^{-1})$

In an ionic solid compound,$A$ ions are at the corners of the cube and $B$ ions are at the center of each face. The molecular formula of the compound will be ..............

What is the type of hole occupied if the limiting value of $\frac{r+}{r-}$ is in the range of $0.225$ to $0.414$?

In a compound $AB_2O_4$,the oxide ions form a cubic close-packed $(CCP)$ lattice. The molar ratio of trivalent cations to bivalent cations is $2:1$. If all the bivalent ions occupy octahedral voids and trivalent ions occupy both tetrahedral and octahedral voids in equal numbers,then the fraction of octahedral voids that remain unoccupied is:

Potassium hexachloroplatinate $(K_2PtCl_6)$ adopts an antifluorite crystal structure. The corners and face centers of the cubic unit cell are occupied by :-

$A$ compound forms a hexagonal close-packed $(HCP)$ structure. What is the total number of voids in $0.5 \ mol$ of it? How many of these are tetrahedral voids?