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

Which type of crystal defect is observed in the diagram given below?
$Na^{+} Cl^{-} Na^{+} Cl^{-} Na^{+} Cl^{-}$
$Cl^{-} \square Cl^{-} Na^{+} \square Na^{+}$
$Na^{+} Cl^{-} \square Cl^{-} Na^{+} Cl^{-}$
$Cl^{-} Na^{+} Cl^{-} Na^{+} \square Na^{+}$

Schottky defect and Frenkel defect are ....... .

Explain the defects arising due to anionic vacancies and due to the presence of extra cations in the interstitial sites.

It is observed that $Li_2O$ is soluble in $NiO$ in small amounts,where $Li^+$ ions occupy some of the cation sites. Which of the following conclusions can be drawn?

In the laboratory,sodium chloride is made by burning sodium in an atmosphere of chlorine. The resulting crystal is yellow in color. The cause of this yellow color is: