In an ionic solid,equal number of cations and anions are missing from their regular positions in the crystal lattice,creating vacancies. This is called-

If molten $NaCl$ contains $SrCl_2$ as impurity,crystallization can generate

When $Fe_{0.93}O$ is heated in the presence of oxygen,it converts to $Fe_2O_3$. The number of correct statement$(s)$ from the following is:
$A.$ The equivalent weight of $Fe_{0.93}O$ is $\frac{\text{Molecular weight}}{0.79}$.
$B.$ The number of moles of $Fe^{2+}$ and $Fe^{3+}$ in $1 \text{ mole}$ of $Fe_{0.93}O$ is $0.79$ and $0.14$ respectively.
$C.$ $Fe_{0.93}O$ is metal deficient with a lattice comprising of a cubic closed-packed arrangement of $O^{2-}$ ions.
$D.$ The $\%$ composition of $Fe^{2+}$ and $Fe^{3+}$ in $Fe_{0.93}O$ is $85\%$ and $15\%$ respectively.

Calculate the percentage of $Fe^{+2}$ in $Fe_{0.95}O$.

Explain the following term with a suitable example:
$(i)$ Schottky defect

Due to $Schottky$ defect: