$F$-centres are formed in $NaCl$ crystal if it is heated with $Na$ vapour. The above is due to

The formula of a metal oxide is $M_{0.96} O_1$. The fractions of metal that exist as $M^{3+}$ and $M^{2+}$ ions in that oxide are respectively

Write a short note on Frenkel defect and Schottky defect.

In ionic compounds where the sizes of the cation and anion are almost similar,which defect is observed?

Which of the following molecular formula and type of defect are correct for the following statement?
"In $FeO$ crystal,some $Fe^{2+}$ ions are missing and the loss of positive charge is made up by the presence of $Fe^{3+}$ ions".

Schottky defect in a crystal is observed when,