Question

Which from following ionic crystals exhibits Frenkel defect?

• A. \(\text{ZnS}\)
• B. \(\text{NaCl}\)
• C. \(\text{KCl}\)
• D. \(\text{KBr}\)

Hint:

Frenkel defect needs a small cation and a large size difference between ions, as in ZnS.

Answer 1

The Correct Option is A

Step 1: Idea:
Frenkel defect is a dislocation defect where the cation moves to an interstitial site.

Step 2: Pick:
Only ZnS has a very small cation next to a large anion. The three alkali halides listed form Schottky defect, in which equal numbers of cations and anions are missing.

Final Answer:
ZnS shows Frenkel defect, option (A). \[ \boxed{\text{ZnS}} \]