What type of defect can arise when a solid is heated? Which physical property is affected by it and in what way?

$KBr$ 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 : $K = 39.1 \ u$,$Br = 79.9 \ u$; $N_A = 6.023 \times 10^{23} \ mol^{-1}$]

In which crystal is the Schottky defect observed?

Explain the following term with a suitable example:
$(ii)$ Frenkel defect

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:

When $NaCl$ (molten) is doped with $10^{-5} \, mol \, \%$ of $AlCl_3$,what is the concentration of cation vacancies?