Question

Which of the following points defects are shown by $AgB{r}_{\left(s\right)}$ crystals?
(I) Schottky defect
(II) Frenkel defect
(III) Metal defect
(IV) Metal deficiency defect

• A. (I) and (II)
• B. (III) and (IV)
• C. (I) and (III)
• D. (II) and (IV)

Answer 1

The correct option is A (I) and (II)

$AgBr$ shows both Schottky and Frenkel defects. In $AgBr$, both $A{g}^{+}$ and $B{r}^{-}$ ions are absent from the lattice causing a Schottky defect. However, $A{g}^{+}$ ions are mobile so they have a tendency to move aside the lattice and trapped in the interstitial site, hence cause Frenkel defect.

Hence, Option "A" is the correct answer.