Question

Match List-I with List-II.

List - I		List - II
A.	Vacancy Defect	I.	Equal number of cations and anions missing
B.	Interstitial Defect	II.	Ion leaves regular site and occupies interstitial site
C.	Schottky Defect	III.	Missing atom from lattice site
D.	Frenkel Defect	IV.	Extra atom at interstitial site

• A. A-III, B-IV, C-I, D-II
• B. A-I, B-II, C-III, D-IV
• C. A-II, B-I, C-IV, D-III
• D. A-IV, B-III, C-II, D-I

Hint:

Schottky defect is vacancy pair defect, while Frenkel defect is vacancy plus interstitial defect.

Answer 1

The Correct Option is A

Concept:
Point defects in crystals include vacancies, interstitials, Schottky defects and Frenkel defects.

Step 1: Vacancy defect.
Vacancy defect means an atom is missing from its regular lattice site. \[ A\rightarrow III \]

Step 2: Interstitial defect.
Interstitial defect means an extra atom occupies an interstitial position. \[ B\rightarrow IV \]

Step 3: Schottky defect.
Schottky defect occurs when equal number of cations and anions are missing from the crystal to maintain electrical neutrality. \[ C\rightarrow I \]

Step 4: Frenkel defect.
Frenkel defect occurs when an ion leaves its regular site and occupies an interstitial site. \[ D\rightarrow II \] Therefore: \[ A-III,\ B-IV,\ C-I,\ D-II \] \[ \therefore \text{Correct Answer is (A)} \]