Which one of the following compounds can show Frenkel defect ?

Options

A. ZnS
B. AgCl
C. Agl
D. All of these

Answer

To determine which of the given compounds can show a Frenkel defect, we need to understand what a Frenkel defect is and the characteristics of the compounds listed.

### Step-by-Step Solution:

1. **Understanding Frenkel Defect:**
- A Frenkel defect is a type of point defect in a crystal lattice where an ion (usually a smaller ion) leaves its normal position and occupies an interstitial site (a space between the regular lattice points). This defect typically occurs in ionic solids where there is a significant difference in the sizes of the cations and anions.

2. **Analyzing the Compounds:**
- We have four options: ZnS, AgCl, AgI, and "all of these."
- We need to check if each compound can exhibit a Frenkel defect based on the size difference between cations and anions.

3. **Option 1: ZnS (Zinc Sulfide)**
- ZnS has a cation (Zn²⁺) and an anion (S²⁻). The size difference between Zn²⁺ and S²⁻ is significant, allowing for the possibility of a Frenkel defect.

4. **Option 2: AgCl (Silver Chloride)**
- In AgCl, the cation (Ag⁺) and anion (Cl⁻) also have a considerable size difference. Therefore, AgCl can also exhibit a Frenkel defect.

5. **Option 3: AgI (Silver Iodide)**
- Similarly, AgI consists of Ag⁺ and I⁻ ions, which have a large size difference. Thus, AgI can also show a Frenkel defect.

6. **Option 4: All of These**
- Since all three compounds (ZnS, AgCl, and AgI) can exhibit Frenkel defects due to the significant size difference between their cations and anions, the correct answer is "all of these."

### Conclusion:
The correct answer is **Option 4: All of these** can show Frenkel defect.

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