Which of the following point defects are shown by $AgBr_{(s)}$ crystals?
$A$. Schottky defect
$B$. Frenkel defect
$C$. Metal excess defect
$D$. Metal deficiency defect

$KBr$ is doped with $10^{-5}$ mole percent of $SrBr_2$. The number of cationic vacancies in $1 \ g$ of $KBr$ crystal is ........ $\times 10^{14}$. (Round off to the Nearest Integer).
[Atomic Mass : $K = 39.1 \ u$,$Br = 79.9 \ u$; $N_A = 6.023 \times 10^{23} \ mol^{-1}$]

When $SrCl_2$ is added to molten $NaCl$ and crystallized,the defect formed is ........

If $10^{-4} \% SrCl_2$ is added to a crystal of $NaCl$,find the number of cationic vacancies created in the crystal.

When $KCl$ is heated in an atmosphere of $K$ vapor,it appears violet. This is because .................

Which of the following is an incorrect statement?