Which one of the following has Frenkel defect?

When $AgCl$ is doped with $10^{-4} \, \text{mole percent}$ $RuCl_3$,what will be the concentration of cationic vacancies per mole of $AgCl$?

In $AgBr$ crystal,the ion size lies in the order $Ag^{+} << Br^{-}$. The $AgBr$ crystal should have the following characteristics:

The appearance of colour in solid alkali metal halides is generally due to

Which of the following solids does not exhibit Frenkel defect?

The formula of a metal oxide with a metal deficiency defect in its crystal is $A_{0.8}O$. The crystal contains $A^{2+}$ and $A^{3+}$ ions. The fraction of metal existing as $A^{2+}$ ions in the crystal is -