Match the types of defect given in column I with the statement given in column II
 

	Column I		Column II
A)	Impurity defect	i)	NaCl with anionic sites called  F-cen tres
B)	Metal excess defect	2)	FeO with ${\mathrm{Fe}}^{3+}$
C)	Metal deficiency defect	3)	NaCl with ${\mathrm{Sr}}^{2+}$ And some cationic sites vacant

	A)	B)	C)
1)	i	ii	iii
2)	iii	i	ii
3)	iii	i	i
4)	i	iii	ii

A. impurity defect arises due to replacement of one common ion present in any crystal by another uncommon ion.

B. Metal excess defect is due to missing of cation from ideal lonic solid which lead to create a F-centre generally occupied by unpaired electrons. e.g., NaCI with anionic site.

C. Metal deficiency defect in FeO, ${\mathrm{Fe}}^{3+}$exists along with ${\mathrm{Fe}}^{3+}$which lead to decrease in metal ion (s) so this is a type of metal deficiency defect.