$1 \ \text{mole}$ of $NaCl$ is doped with $10^{-5} \ \text{mole}$ of $SrCl_{2}$. The number of cationic vacancies in the crystal lattice will be:

What type of stoichiometric defect is shown by:
$(i)$ $ZnS$
$(ii)$ $AgBr$

$A$ silicon specimen is made into a $p-$type semiconductor by doping,on an average,one indium atom per $5 \times 10^7$ silicon atoms. If the number density of atoms in the silicon specimen is $5 \times 10^{28} \ \text{atoms} \ m^{-3}$,then the number of acceptor atoms in silicon per cubic centimeter will be

$A$ metallic solid undergoes Frenkel defect. Its original mass,volume and density are $M_0$,$V_0$ and $D_0$ respectively. After Frenkel defect the mass,volume and density are $M$,$V$ and $D$ respectively. The variations of $M$,$V$ and $D$ after Frenkel defect are

Explain stoichiometric defects shown by non-ionic solids.

An element $X$ (atomic weight = $24$) crystallises in a face-centered cubic $(FCC)$ lattice. The edge length of the unit cell is $400 \, pm$. If this lattice contains $4\%$ Schottky defects,calculate the observed density of this element in $g/cm^3$ $(N_A = 6 \times 10^{23})$.