Question

Match the defects given in column I with statements given in column II and mark the appropriate choice.

	Column I		Column II
(A)	Simple vacancy defect	(i)	Shown by non-ionic solids and increases the density of the solid.
(B)	Simple interstitial defect	(ii)	Shown by ionic solution and decreases the density of the solid
(C)	Frenkel defect	(iii)	Shown by non-ionic solids and decreases the density of the solid
(D)	Schottky defect	(iv)	Shown by ionic solids and density of the solid remains the same

• A. (A)$\to$(iv), (B)$\to$(iii), (C)$\to$(ii), (D)$\to$(i)
• B. (A)$\to$(iii), (B)$\to$(iv), (C)$\to$(i), (D)$\to$(ii)
• C. (A)$\to$(iii), (B)$\to$(i), (C)$\to$(iv), (D)$\to$(ii)
• D. (A)$\to$(i), (B)$\to$(iii), (C)$\to$(iv), (D)$\to$(ii)

Answer 1

Answer: (C)

(A)$\to$(iii), (B)$\to$(i), (C)$\to$(iv), (D)$\to$(ii)

• Simple vacancy defect: It is a kind of point defect in which an atom is missing from one of the lattice sites. In this, the density of the crystal decreases. It is generally shown by non-ionic solids.
  
• Simple interstitial defect: It is a kind of point defect in which an atom moves from its regular lattice site to one of the interstitial sites. The density of the crystal remains same in the crystals showing this defect. It is generally shown by non-ionic solids.
  
• Frenkel Defect: It is a kind o defect in crystalline solids in which atoms are displaced from their lattice position to interstitial site creating a vacancy at the lattice point. It usually occurs in ionic solid with a large difference in the size of ions. The density of crystal remains unchanged.

• Schottky Defect: This defect occurs when oppositely charged ions leave their lattice site creating vacancies in such a way that electrical neutrality of crystal is maintained. It is generally seen in highly ionic compounds where the difference in size of cation and anion is small. So. An equal number of cation and anion vacancies are present in the crystals with Schottky Defect. The density of the crystal decreases in this defects.