Ionic solids,with Schottky defects,contain in their structure

$NaCl$ is heated in an atmosphere of sodium vapour. The resultant yellow colour is due to the formation of

Non-stoichiometric defects do not include which of the following?

Metal deficiency defect is shown by $Fe_{0.93}O$. In the crystal,some $Fe^{2+}$ cations are missing and loss of positive charge is compensated by the presence of $Fe^{3+}$ ions. The percentage of $Fe^{2+}$ ions in the $Fe_{0.93}O$ crystals is $....$ (Nearest integer)

Non-stoichiometric cuprous oxide,$Cu_{2}O$ can be prepared in the laboratory. In this oxide,the copper to oxygen ratio is slightly less than $2:1$. Can you account for the fact that this substance is a $p$-type semiconductor?

Which type of defect is observed in crystals like $NaCl$ and $KCl$?